Blueprint API: PackageContext is now an Interface

Change-Id: I656ae3b4657514faa4a1d12d6a33e9cefd8efb84
diff --git a/common/module.go b/common/module.go
index e11082e..1683671 100644
--- a/common/module.go
+++ b/common/module.go
@@ -372,7 +372,7 @@
 	checkbuildFiles []string
 }
 
-func (a *androidModuleContext) Build(pctx *blueprint.PackageContext, params blueprint.BuildParams) {
+func (a *androidModuleContext) Build(pctx blueprint.PackageContext, params blueprint.BuildParams) {
 	params.Optional = true
 	a.ModuleContext.Build(pctx, params)
 }