Further fixes for ssl_passphrase_callback test module.

The Makefile should set TAP_TESTS = 1, not implement the infrastructure
for itself.  For one thing, it missed the appropriate "make clean"
steps.  For another, the buildfarm isn't running this test because
it wasn't hooked into "make installcheck" either.

src/test/modules/ssl_passphrase_callback/Makefile

-# ssl_passphrase Makefile
+# ssl_passphrase_callback Makefile
 
 export with_openssl
 
@@ -6,6 +6,8 @@ MODULE_big = ssl_passphrase_func
 OBJS = ssl_passphrase_func.o $(WIN32RES)
 PGFILEDESC = "callback function to provide a passphrase"
 
+TAP_TESTS = 1
+
 ifdef USE_PGXS
 PG_CONFIG = pg_config
 PGXS := $(shell $(PG_CONFIG) --pgxs)
@@ -18,9 +20,3 @@ include $(top_srcdir)/contrib/contrib-global.mk
 endif
 
 SHLIB_LINK += $(filter -lssl -lcrypto -lssleay32 -leay32, $(LIBS))
-
-check: prove-check
-
-prove-check: ssl_passphrase_func$(DLSUFFIX) | temp-install
-	@echo running prove ...
-	$(prove_check)