shill: Mark CellularService as connectable.

BUG=chromium-os:30804
TEST=Unit tests, network_3GModemControl

Change-Id: I1adedba6fefa0c9d7d7bd2eab4e54deabc2f529d
Reviewed-on: https://gerrit.chromium.org/gerrit/22628
Reviewed-by: Gary Morain <gmorain@chromium.org>
Tested-by: Thieu Le <thieule@chromium.org>
Commit-Ready: Thieu Le <thieule@chromium.org>
diff --git a/cellular_service.cc b/cellular_service.cc
index de5788c..f5712ac 100644
--- a/cellular_service.cc
+++ b/cellular_service.cc
@@ -92,6 +92,7 @@
     : Service(control_interface, dispatcher, metrics, manager,
               Technology::kCellular),
       cellular_(device) {
+  set_connectable(true);
   PropertyStore *store = this->mutable_store();
   store->RegisterConstString(flimflam::kActivationStateProperty,
                              &activation_state_);