interface: Modified protobuf generator to use the basename of the .proto file...

interface: Modified protobuf generator to use the basename of the .proto file as basis for the resulting *ServiceClient classes.

Revision 2893 resulted in a rename of "DIRServiceClient" to "DirectoryServiceClient" in order to fix issue 248. This commit reverts the rename. Now the name scheme for the ServiceClient classes is consistent again and issue 248 still should be fixed.

git-svn-id: https://xtreemfs.googlecode.com/svn/trunk@2897 f8528748-c2c0-11dd-ba5c-d3b7c2b3b534