Adds webkit revision to the summary and details.

The revision number is taken from external/webkit/WEBKIT_MERGE_REVISION and is served to the java code by apache server. To be able to do that, the new alias directive had to be
added to the run_apache2.py script.

Bug: 28895725
Change-Id: Ie3d147e4d8ea9edd0144b819152121563b8bd759