RFR 7191662: JCE providers should be located via ServiceLoader

[Valerie Peng]

Hi, build experts,

Can you please review the make file related change, i.e. the new file || 
*make/gensrc/Gensrc-java.naming.gmk*, in the following webrev:
http://cr.openjdk.java.net/~valeriep/7191662/webrev.01/

This is for merging the java.security.Provider file from various 
providers and use the (merged) result for the final image build.

The rest of source code changes are reviewed by my team already.
Thanks,
Valerie
(Java Security Team)