[eclipselink-dev] patch for 344837 - Extensibility Metadata Repository c

[Christopher Delahunt <christopher.delahunt@xxxxxxxxxx>]

https://bugs.eclipse.org/bugs/show_bug.cgi?id=344837

This changes interface MetadataRepositoryReader to be MetadataSource, 
and changes all instances of Repository to Source in comments, hints and 
variable names.
It includes a fix to XMLMetadataSource so that it will use properties 
passed in as well as those defined in the persistence.xml

Checked into main at revision 9372
Reviewed by Guy