manifest: fork android_build

Change-Id: I87eb66a64b9b4d3068b6db4ccf4bba613f988ac1

default.xml

@@ -16,7 +16,7 @@
            sync-c="true"
            sync-j="4" />
 
-  <project path="build" name="platform/build" groups="pdk,tradefed" >
+  <project path="build" name="android_build" remote="omnirom" revision="android-7.0" groups="pdk,tradefed" >
     <copyfile src="core/root.mk" dest="Makefile" />
   </project>
   <project path="build/blueprint" name="platform/build/blueprint" groups="pdk,tradefed" />