updgrade gradle plugin

.travis.yml

@@ -7,7 +7,6 @@ android:
     - tools
     - build-tools-26.0.1
     - android-25
-    - extra-android-m2repository
     - extra-google-m2repository
     - extra-google-google_play_services
   licenses:

build.gradle

@@ -4,9 +4,12 @@ buildscript {
     repositories {
         jcenter()
         mavenCentral()
+        maven {
+            url 'https://maven.google.com'
+        }
     }
     dependencies {
-        classpath 'com.android.tools.build:gradle:2.3.0'
+        classpath 'com.android.tools.build:gradle:2.3.3'
     }
 }
 

libs/MemorizingTrustManager/build.gradle

@@ -2,6 +2,7 @@ buildscript {
 	repositories {
 		mavenCentral()
 	}
+	
 	dependencies {
 		classpath 'com.android.tools.build:gradle:2.3.0'
 	}