Perforce does not strictly require the usage of branch specifications to create
branches. In these cases the branch detection code of git-p4 will not be able to
import them.
This patch adds support for git-p4.branchList configuration option, allowing
branches to be defined in git config.
Signed-off-by: Vitor Antunes <vitor.hda@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>