Re-enable -Wall and -Werror that were lost in a merge

-Wall and -Werror were lost during a merge when they were added to
aaptCFLAGS instead of aaptCFlags.  Fix the typo, and the warnings
that crept in while it was disabled.

Change-Id: Ib944b8d6149278e4f3861c1acac277bcd95cc7c2
diff --git a/tools/aapt/Android.mk b/tools/aapt/Android.mk
index c5495a5..9956bd7 100644
--- a/tools/aapt/Android.mk
+++ b/tools/aapt/Android.mk
@@ -67,7 +67,7 @@
     libziparchive-host
 
 aaptCFlags := -DAAPT_VERSION=\"$(BUILD_NUMBER)\"
-aaptCFLAGS += -Wall -Werror
+aaptCFlags += -Wall -Werror
 
 ifeq ($(HOST_OS),linux)
     aaptHostLdLibs += -lrt -ldl -lpthread