qisrc: WorkTreeSyncer: remove synonym
qisrc: WorkTreeSyncer: remove synonym

get_new_repos is called at only one place and does the same thing
as read_remote_manifest

Change-Id: I9544f320498db20d1979c56f8d18e49e63820478
Reviewed-on: http://gerrit.aldebaran.lan/55472
Tested-by: gerrit
Reviewed-by: dmerejkowsky <1e4b13000fa8777df4cefd2fd8215187e3deb062@aldebaran-robotics.com>

aldebaran/qibuild,aldebaran/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,aldebaran/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild,dmerejkowsky/qibuild