PlacePicker in Android not working in Signed APK

Question

I have Implemented PlacePicker in my Application. Its working fine in test cases. But the same thing is not working in Signed APK. I dont know how to fix this issue and so far googling not helped me. Seeking some help here.

Code Part

 @Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    mButton = (Button) findViewById(R.id.mButton);
    mTExt = (TextView) findViewById(R.id.mTExt);

    mButton.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            try {
                PlacePicker.IntentBuilder builder = new PlacePicker.IntentBuilder();
                startActivityForResult(builder.build(MainActivity.this), PLACE_PICKER_REQUEST);
            } catch (GooglePlayServicesRepairableException e) {
                e.printStackTrace();
            } catch (GooglePlayServicesNotAvailableException e) {
                e.printStackTrace();
                Log.e(TAG, e.getMessage());
            }
        }
    });
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == PLACE_PICKER_REQUEST
            && resultCode == Activity.RESULT_OK) {

        final Place place = PlacePicker.getPlace(this, data);
        final CharSequence name = place.getName();
        final CharSequence address = place.getAddress();
        String attributions = (String) place.getAttributions();
        if (attributions == null) {
            attributions = "null";
        }
        mTExt.setText("Name: " + name + "\n Address: " + address);

    } else {
        super.onActivityResult(requestCode, resultCode, data);
    }
}

AndroiManifest.xml

<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">

    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />
    <meta-data
        android:name="com.google.android.geo.API_KEY"
        android:value="Here I entered my API key" />

    <activity android:name=".MainActivity">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
</application>