Make "make clean" rules a bit more standard.

Summary:
make-generic is some sort of internal undocumented thing.
make-local is what is supposed to be used for this stuff.
Also use $(RM) instead of "rm -f".

Reviewed By: marc

Test Plan: make clean


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665498 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/lib/java/Makefile.am b/lib/java/Makefile.am
index 2aa5714..46c02ee 100644
--- a/lib/java/Makefile.am
+++ b/lib/java/Makefile.am
@@ -4,7 +4,7 @@
 install-exec-hook:
 	$(ANT) install
 
-clean-generic:
+clean-local:
 	$(ANT) clean
 
 check-local: all