Merge branch 'jc/sign-buffer-failure-propagation-fix'

A failed "git tag -s" did not necessarily result in an error
depending on the crypto backend, which has been corrected.

* jc/sign-buffer-failure-propagation-fix:
  ssh signing: signal an error with a negative return value
  tag: fix sign_buffer() call to create a signed tag

builtin/tag.c

@@ -153,7 +153,7 @@ static int verify_tag(const char *name, const char *ref UNUSED,
 
 static int do_sign(struct strbuf *buffer)
 {
-	return sign_buffer(buffer, buffer, get_signing_key());
+	return sign_buffer(buffer, buffer, get_signing_key()) ? -1 : 0;
 }
 
 static const char tag_template[] =