Move back to gradle version + plugin that doesn't hang.

New version hangs when running:
./gradlew :library:assembleAndroidTest --debug

Android Studio "strongly recommends" we upgrade to the
hanging version, but I guess we'll just have to ignore
that until the latest version works again!

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=132063280

build.gradle

@@ -20,7 +20,7 @@ buildscript {
         jcenter()
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.2.0-beta3'
+        classpath 'com.android.tools.build:gradle:2.1.2'
         classpath 'com.novoda:bintray-release:0.3.4'
     }
 }

gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.14.1-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-2.10-all.zip