Adopt the new prebuilts/ndk/<number> paths.

Bug: 6932421
Change-Id: I42b62b521222991b372610b26a54ebf6c34bf714
diff --git a/libstlport.mk b/libstlport.mk
index f9d696f..8c726f8 100644
--- a/libstlport.mk
+++ b/libstlport.mk
@@ -1,7 +1,7 @@
 # Add a couple include paths to use stlport.
 
 ifdef LOCAL_NDK_VERSION
-stlport_NDK_VERSION_ROOT := $(HISTORICAL_NDK_VERSIONS_ROOT)/android-ndk-r$(LOCAL_NDK_VERSION)/platforms/android-$(LOCAL_SDK_VERSION)/arch-$(TARGET_ARCH)
+stlport_NDK_VERSION_ROOT := $(HISTORICAL_NDK_VERSIONS_ROOT)/$(LOCAL_NDK_VERSION)/platforms/android-$(LOCAL_SDK_VERSION)/arch-$(TARGET_ARCH)
 LOCAL_C_INCLUDES := \
 	$(stlport_NDK_VERSION_ROOT) \
 	external/stlport/stlport \