gitlab: improve checking for project lookup during fork
gitlab: improve checking for project lookup during fork

The fork was being interrupted only when another fork, for a different
project, was found. However, there are other cases where a fork should fail:
(keep in mind the code is trying to find an identical _fork project_)

1) the fork matches the project being forked

	creates two remotes pointing to the exact same project.

2) the fork matches a non-forked project

	creates a remote pointing to a project, that just matches the
	namespace/name the user wants, but it isn't a fork.

	In general, it falls in case 1), however, lab allow the user to set a
	custom name, namespace and path for the fork, so we need this additional
	checking step.

3) (as said above) the fork matches another fork, but for a different project

	create a remote pointing to a project with same namespace/name but
	forked from another non-related project.

Signed-off-by: Bruno Meneguele <82c7731bc2625bcbab88bc571aee6631ba3f66f3@redhat.com>

zaquestion/lab,zaquestion/lab