pwclient: add project option to single-patch commands

pwclient: add project option to single-patch commands

Previously, we could not target a particular server instance with the
apply, git-am, info, and view subcommands. Under a single-server design,
we never needed to target a particular project for a patch. We just
targeted the patch itself. But with the advent of multi-server
.pwclientrc configurations, we should allow pwclient to specify the
project for these commands.

This adds the '-p PROJECT' option to:
 * apply
 * git-am
 * info
 * view

Signed-off-by: Brian Norris <computersforpeace@gmail.com>
Signed-off-by: Jeremy Kerr <jk@ozlabs.org>