[dispatch] warning: minor workflow change - clean up config.sh

[Alan Conway <ac...@redhat.com>]

This commit will cause a minorchange in workflow so I wanted to warn
everyone. Instead of:
   . config.sh
it will be 
   . <build>/config.sh

and instead of:
   . config.sh; bin/test.sh
it will be just
    ./test.sh

See below for details. If nobody yells I'll check this in in a few days:

----

NO-JIRA: Ratiaonlize config.sh and test.sh

The config.sh in the dispatch/ root dir has a couple of problems:

- redundant given the generated config.sh in a build.
- not useful if you have several builds.
- clashes with the generated config.sh in an in-tree build.

This is a small simplification that preserves the
one-button test.sh and gets rid of the redundant config.sh:

- removed dispatch/config.sh
- moved dispatch/bin/test.sh to dispatch/test.sh

One button to clean, build, install and test with no prior env. setup:

    cd dispatch; ./test.sh

By default this removes and re-builds/re-installs the build/ and
install/ subdirs, but you can specifiy alternate build and install
subdirs.

For any build directory:

    source <build>/config.sh

will set up paths so you can run executables, script or tests from that
build on the command line.

As before the generated <build>/run.py is used by cmake so it can work
withouut prior env. settings.