Bugfix: Having 'ssh' as a file in the path was causing problems

Changing it back to a function seems to work great.  The main problem with it as
a binary file is that when other commands attempted to execute it, it would
fail.  For example, all `git push` commands (or any git commands) which used SSH
would hang indefinitely.

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Change-Id:     I22c53ccbe582e7e99ee92eebfddbe41174879cc6
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>