remove test/.rnd on make clean

Reviewed-by: NRichard Levitte <levitte@openssl.org>
Reviewed-by: NRich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2344)

Configurations/unix-Makefile.tmpl

@@ -290,6 +290,7 @@ clean: libclean
 	-$(RM) `find . -name '*{- $objext -}' -a \! -path "./.git/*"`
 	$(RM) core
 	$(RM) tags TAGS
+	$(RM) test/.rnd
 	$(RM) openssl.pc libcrypto.pc libssl.pc
 	-$(RM) `find . -type l -a \! -path "./.git/*"`
 	$(RM) $(TARFILE)