Pin libraries needed by vogar tool to java 1.7

vogar still uses javac/dx by default. dx does not
handle v52 class files. The default java version
is going to switch to 1.8. This change pins the
targets need by vogar to 1.7.

Bug: 26753820
Bug: 27310428
Change-Id: I5f2afc889067b3f8d192d02f4d48c7d5bd53a584
diff --git a/Android.mk b/Android.mk
index 4ddaa58..21ff612 100644
--- a/Android.mk
+++ b/Android.mk
@@ -29,6 +29,7 @@
 LOCAL_JAVA_LIBRARIES := junit objenesis-host ant
 LOCAL_MODULE := mockito-host
 LOCAL_MODULE_TAGS := optional
+LOCAL_JAVA_LANGUAGE_VERSION := 1.7
 include $(BUILD_HOST_JAVA_LIBRARY)