Allow packages to place manifest files in any directory

via a new definition LOCAL_ABS_MANIFEST_FILE.  The existing
LOCAL_MANIFEST_FILE variable will also be supported.

(Necessary if manifests are being programmatically generated in the
intermediates directory)

Change-Id: I77a8eb1b8040b966b944464281d00c161ff34d3c
diff --git a/core/clear_vars.mk b/core/clear_vars.mk
index c6fd06b..857cdc7 100644
--- a/core/clear_vars.mk
+++ b/core/clear_vars.mk
@@ -104,6 +104,7 @@
 LOCAL_PROGUARD_FLAG_FILES:=
 LOCAL_EMMA_COVERAGE_FILTER:=
 LOCAL_WARNINGS_ENABLE:=
+LOCAL_FULL_MANIFEST_FILE:=
 LOCAL_MANIFEST_FILE:=
 LOCAL_RENDERSCRIPT_INCLUDES:=
 LOCAL_RENDERSCRIPT_INCLUDES_OVERRIDE:=