[TOMAHAWK] Minor optimization in StreamingAddResource class

[David Brainard <sd...@gmail.com>]

Hi,

In the method mentioned below[1] rather than checking contains key  the 
whole code can be replaced with the code mentioned below[2] because this 
will reduce the no of times contains  is performed on the set.
[1]
private boolean checkAlreadyAdded(PositionedInfo info)
    {
        Long key = new Long(info.hashCode());
        if (alreadySeenResources.contains(key))
        {
            return true;
        }
        alreadySeenResources.add(key);
        return false;
    }

[2]
private boolean checkAlreadyAdded(PositionedInfo info)
    {
         return !alreadySeenResources.add(new Long(info.hashCode()));
    }

if it is appropriate pls comment and i'l open a issue in jira .

Regards,
David Brainard