gradle: fix demo build.gradle

demo/build.gradle

@@ -11,7 +11,7 @@
 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 // See the License for the specific language governing permissions and
 // limitations under the License.
-apply plugin: 'android'
+apply plugin: 'com.android.application'
 
 android {
     compileSdkVersion 19
@@ -23,7 +23,7 @@ android {
     }
     buildTypes {
         release {
-            runProguard false
+            minifyEnabled false
             proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.txt'
         }
     }