Merge branch 'jt/format-patch-from-config'

"git format-patch" learned format.from configuration variable to
specify the default settings for its "--from" option.

* jt/format-patch-from-config:
  format-patch: format.from gives the default for --from

contrib/completion/git-completion.bash

@@ -2182,6 +2182,7 @@ _git_config ()
 		format.attach
 		format.cc
 		format.coverLetter
+		format.from
 		format.headers
 		format.numbered
 		format.pretty