Merge branch 'sg/t-helper-gitignore'

Update the way build artifacts in t/helper/ directory are ignored.

* sg/t-helper-gitignore:
  t/helper: ignore only executable files

Author: gitster

t/helper/.gitignore

@@ -1,5 +1,4 @@
-*
-!*.sh
-!*.[ch]
-!*.gitignore
-
+/test-tool
+/test-fake-ssh
+/test-line-buffer
+/test-svn-fe