Display git pull download URLs on patch sets

This change shows "git pull ..." command lines for fetching
a patch set down off Gerrit using standard Git tools, rather
than relying upon the "repo download" command.  It also makes
the usage of "repo download" more optional by not showing the
repo download command line by default.

If a project is not readable by anonymous users then we offer
an SSH URL instead of an anonymous git:// URL.

Bug: GERRIT-55
Signed-off-by: Shawn O. Pearce <sop@google.com>
11 files changed