maintner/cmd/maintserve: fix redirect logic
maintner/cmd/maintserve: fix redirect logic

There was a typo in the redirection code, causing invalid logic.
This change fixes it.

Change-Id: I71f1e98fff488689c988eb72a83b37e031d35b87
Reviewed-on: https://go-review.googlesource.com/56251
Reviewed-by: Kevin Burke <685caccd7011cfe58b8f9ef79ff9dca388f03c79@inburke.com>

golang/build,golang/build,golang/build,golang/build