zeppelin git commit: [ZEPPELIN-2827] Spark's pyspark fails if unsupported version of matplotlib is present

[pr...@apache.org]

Repository: zeppelin
Updated Branches:
  refs/heads/master f238ca0e3 -> 89e2e0246


[ZEPPELIN-2827] Spark's pyspark fails if unsupported version of matplotlib is present

### What is this PR for?
%spark.pyspark paragraphs keep running for more than > 5 minutes and then at the end, throw TTransportException.

```
org.apache.thrift.transport.TTransportException
	at org.apache.thrift.transport.TIOStreamTransport.read(TIOStreamTransport.java:132)
	at org.apache.thrift.transport.TTransport.readAll(TTransport.java:86)
	at org.apache.thrift.protocol.TBinaryProtocol.readAll(TBinaryProtocol.java:429)
	at org.apache.thrift.protocol.TBinaryProtocol.readI32(TBinaryProtocol.java:318)
	at org.apache.thrift.protocol.TBinaryProtocol.readMessageBegin(TBinaryProtocol.java:219)
	at org.apache.thrift.TServiceClient.receiveBase(TServiceClient.java:69)
```

This happens because Zeppelin refers to `matplotlib.rcParams['savefig.format']` https://github.com/apache/zeppelin/blob/master/interpreter/lib/python/mpl_config.py#L83 which is only present in matplotlib 1.2.0 (https://github.com/matplotlib/matplotlib/blob/v1.2.0/matplotlibrc.template#L355) and onwards.

### What type of PR is it?
[Bug Fix]

### What is the Jira issue?
* [ZEPPELIN-2827](https://issues.apache.org/jira/browse/ZEPPELIN-2827)

### How should this be tested?
Try running spark.pyspark on a machine with matplotlib==1.1.1 installed, pyspark should work as expected.

### Questions:
* Does the licenses files need update? N/A
* Is there breaking changes for older versions? N/A
* Does this needs documentation? N/A

Author: Prabhjyot Singh <pr...@gmail.com>

Closes #2516 from prabhjyotsingh/ZEPPELIN-2827 and squashes the following commits:

0321fcd3e [Prabhjyot Singh] check if `savefig.format` exists in mpl_config.py
da26f5613 [Prabhjyot Singh] add a version check along with check if matplotlib is installed


Project: http://git-wip-us.apache.org/repos/asf/zeppelin/repo
Commit: http://git-wip-us.apache.org/repos/asf/zeppelin/commit/89e2e024
Tree: http://git-wip-us.apache.org/repos/asf/zeppelin/tree/89e2e024
Diff: http://git-wip-us.apache.org/repos/asf/zeppelin/diff/89e2e024

Branch: refs/heads/master
Commit: 89e2e0246c79b84d9cce73ac88727c29e37439f3
Parents: f238ca0
Author: Prabhjyot Singh <pr...@gmail.com>
Authored: Thu Aug 3 22:48:40 2017 -0700
Committer: Prabhjyot Singh <pr...@gmail.com>
Committed: Tue Aug 8 11:38:18 2017 -0700

----------------------------------------------------------------------
 interpreter/lib/python/mpl_config.py | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/zeppelin/blob/89e2e024/interpreter/lib/python/mpl_config.py
----------------------------------------------------------------------
diff --git a/interpreter/lib/python/mpl_config.py b/interpreter/lib/python/mpl_config.py
index e48678f..5c60893 100644
--- a/interpreter/lib/python/mpl_config.py
+++ b/interpreter/lib/python/mpl_config.py
@@ -71,7 +71,11 @@ def _on_config_change():
     supported_formats = _config['supported_formats']
     if fmt not in supported_formats:
         raise ValueError("Unsupported format %s" %fmt)
-    matplotlib.rcParams['savefig.format'] = fmt
+
+    if matplotlib.__version__ < '1.2.0':
+        matplotlib.rcParams.update({'savefig.format': fmt})
+    else:
+        matplotlib.rcParams['savefig.format'] = fmt
     
     # Interactive mode
     interactive = _config['interactive']
@@ -80,6 +84,8 @@ def _on_config_change():
     
 def _init_config():
     dpi = matplotlib.rcParams['figure.dpi']
+    if matplotlib.__version__ < '1.2.0':
+        matplotlib.rcParams.update({'savefig.format': 'png'})
     fmt = matplotlib.rcParams['savefig.format']
     width, height = matplotlib.rcParams['figure.figsize']
     fontsize = matplotlib.rcParams['font.size']