Stop hard coding gmock things.

The headers are exported.

Change-Id: I72f8dda3f441bc72accce3c9e94a7160fcefc54c
Test: mma
(cherry picked from commit a26bcd5424ee0e9cf4d621d85e31551d23a46b13)
diff --git a/tests/input/evdev/Android.mk b/tests/input/evdev/Android.mk
index 3aeb2f8..b892a7f 100644
--- a/tests/input/evdev/Android.mk
+++ b/tests/input/evdev/Android.mk
@@ -2,7 +2,6 @@
 include $(CLEAR_VARS)
 
 LOCAL_C_INCLUDES += hardware/libhardware/modules/input/evdev
-LOCAL_C_INCLUDES += $(TOP)/external/gmock/include
 
 LOCAL_SRC_FILES:= \
     BitUtils_test.cpp \