Improve handling of rpm building

Added default apache configuration file for parity with debian systems
Allow GDESTDIR to specify install location for rpms

Removed vestigial ganglia-web/ganglia-web/debian folder


I'm not 100% positive that the last change is safe.  I couldn't find any references to it anywhere in the debian directory, but I'm not as familiar with debian building as I am with rpms, and I don't have a debian machine handy to test.  But looking through the history, it seems as if it was created and then the references were removed later.