[Build] Clean all coverage files during make clean

This adds extra paths that were left out and ensures that `.gcda` and `
.gcno` files are properly cleaned up.

src/Makefile.am

@@ -532,10 +532,16 @@ CLEANFILES = $(EXTRA_LIBRARIES)
 CLEANFILES += *.gcda *.gcno
 CLEANFILES += compat/*.gcda compat/*.gcno
 CLEANFILES += crypto/*.gcda crypto/*.gcno
+CLEANFILES += libzerocoin/*.gcda libzerocoin/*.gcno
 CLEANFILES += primitives/*.gcda primitives/*.gcno
+CLEANFILES += rpc/*.gcda rpc/*.gcno
 CLEANFILES += script/*.gcda script/*.gcno
+CLEANFILES += support/*.gcda support/*.gcno
 CLEANFILES += univalue/*.gcda univalue/*.gcno
+CLEANFILES += wallet/*.gcda wallet/*.gcno
+CLEANFILES += wallet/test/*.gcda wallet/test/*.gcno
 CLEANFILES += zmq/*.gcda zmq/*.gcno
+CLEANFILES += zpiv/*.gcda zpiv/*.gcno
 CLEANFILES += obj/build.h
 
 EXTRA_DIST =