Rename libkeymaster to libkeymaster_staging

Fix a build breakage by renaming libkeymaster to
libkeymaster_staging. fugu's vendor tree already had
a libkeymaster.so which masked system/keymaster/libkeymaster.

Bug: 37997750
Test: mma -j
Merged-In: I589e9c87c2120034d5709a0d7a141d724065d683
Change-Id: I589e9c87c2120034d5709a0d7a141d724065d683
(cherry picked from commit 5d50d7e6054b42a398c7903326a7fbcab05c5cb8)
diff --git a/keystore/Android.mk b/keystore/Android.mk
index e854772..cef637a 100644
--- a/keystore/Android.mk
+++ b/keystore/Android.mk
@@ -58,7 +58,7 @@
 	libsoftkeymasterdevice \
 	libkeymaster_messages \
 	libkeymaster_portable \
-	libkeymaster \
+	libkeymaster_staging \
 	libhwbinder \
 	libhidlbase \
 	libhidltransport \