fix resources: msisdn must not be too short, start with 1000
diff --git a/src/osmo_gsm_tester/resource.py b/src/osmo_gsm_tester/resource.py
index b842d98..87ea551 100644
--- a/src/osmo_gsm_tester/resource.py
+++ b/src/osmo_gsm_tester/resource.py
@@ -204,7 +204,7 @@
         with self.state_dir.lock(origin_id):
             msisdn_path = self.state_dir.child(LAST_USED_MSISDN_FILE)
             with log.Origin(msisdn_path):
-                last_msisdn = '1'
+                last_msisdn = '1000'
                 if os.path.exists(msisdn_path):
                     if not os.path.isfile(msisdn_path):
                         raise RuntimeError('path should be a file but is not: %r' % msisdn_path)