Rename metrics.cc to metrics_reporter_omaha.cc

Also rename the mock_metrics.h to mock_metrics_reporter.h

Bug: 30989466
Test: unit tests pass
Change-Id: Ic2297b86c61c3e3db7159bc2b00b513d4a9410e3
diff --git a/Android.mk b/Android.mk
index ff12e59..8da8ede 100644
--- a/Android.mk
+++ b/Android.mk
@@ -288,7 +288,7 @@
     hardware_android.cc \
     image_properties_android.cc \
     libcurl_http_fetcher.cc \
-    metrics.cc \
+    metrics_reporter_omaha.cc \
     metrics_utils.cc \
     omaha_request_action.cc \
     omaha_request_params.cc \