Fix 500 error for secret PUT

Two issues here caused failure for secret PUT.

First, constructor for secret wasn't passing in the metadata repo when
saving off to self.repos.  Added the secret_meta_repo to self.repos.

Second the PUT controller wasn't passing in the right value to the plugin
to store the sercret.  It was sending in a function object rather than
the result of calling that function.  Two parens made things all better...

Also updated unit tests.

Change-Id: I89d329c718e10fb3e64c6a81867df86ada22b02e
Closes-Bug: 1339460
Merge "Fix 500 error for secret PUT"