Follow-up for commit 491ea3e

|AndroidProducts.mk| has its own meaning in Android build system.  We
shouldn't have used it unless we're declaring some product variants.
Rename to |Android.mk| and move it into ril/ to prevent from hiding other
|Android.mk| files.
Merge pull request #4 from vicamo/fix-491ea3e

Follow-up for commit 491ea3e. r=me