(Android) Fix paths to build-extras.gradle and gradle.properties (#810)
(Android) Fix paths to build-extras.gradle and gradle.properties (#810)

* Fix paths to build-extras.gradle and gradle.properties

Since cordova-android v7.0 paths to `build-extras.gradle` and `gradle.properties` have changed (see https://github.com/apache/cordova-android/pull/389)

* reword

apache/cordova-docs,apache/cordova-docs,shazron/cordova-docs,purplecabbage/cordova-docs,shazron/cordova-docs,purplecabbage/cordova-docs,shazron/cordova-docs,purplecabbage/cordova-docs,apache/cordova-docs,apache/cordova-docs,purplecabbage/cordova-docs,shazron/cordova-docs