deprecate postbuildscript onsuccess and onfailure parameter names

The postbuildscript module's 'onsuccess' and 'onfailure' parameters
names were slightly confusing.  This change deprecates those parameter
names and replaces them with less confusing names.  The new names
are more closely matched to the ones that get added to the xml.

Change-Id: Ifb76129852816aa3f8ee6bb7f609a2344ccc7a69
Merge "deprecate postbuildscript onsuccess and onfailure parameter names"