Repo should not fetch tags for shallow projects

Fetching all tags for a shallow git results in an
inconstent git and forces git to fetch more than
the depth specified.

This change teaches repo not to fetch any tags in a
repository initialised with the depth option.

Change-Id: I557ead9f88fa0d6a19b1cb55b23bba1100fcb8f2
Signed-off-by: Patrik Ryd <patrik.ryd@stericsson.com>
1 file changed