shill: Use service_constant's kTypeCellular to create storage id.

BUG=chromium-os:24952
TEST=unit tests

Change-Id: I1428887187ab5ec4cc44389997ccc5aac0bfe2a6
Reviewed-on: https://gerrit.chromium.org/gerrit/15226
Commit-Ready: Darin Petkov <petkov@chromium.org>
Reviewed-by: Darin Petkov <petkov@chromium.org>
Tested-by: Darin Petkov <petkov@chromium.org>
diff --git a/cellular_service.cc b/cellular_service.cc
index ea7ea36..897dea2 100644
--- a/cellular_service.cc
+++ b/cellular_service.cc
@@ -17,9 +17,6 @@
 
 namespace shill {
 
-// static
-const char CellularService::kServiceType[] = "cellular";
-
 // TODO(petkov): Add these to system_api/dbus/service_constants.h
 namespace {
 const char kKeyOLPURL[] = "url";
@@ -95,7 +92,8 @@
   store->RegisterConstString(flimflam::kUsageURLProperty, &usage_url_);
 
   set_friendly_name(device->CreateFriendlyServiceName());
-  SetStorageIdentifier("cellular_" + device->address() + "_" + friendly_name());
+  SetStorageIdentifier(string(flimflam::kTypeCellular) + "_" +
+                       device->address() + "_" + friendly_name());
 }
 
 CellularService::~CellularService() { }