do not need to find service when service finded

[zhuantouer]

in org.zpcat.ble.ui.central.CentralDetailsActivity.displayGattServices(): displayGATTServices :
when connected to a GATT server and get the services and characteristics, it is no need to
re-find the service again. I test it on nexus 5, when get into org.zpcat.ble.ui.central.CentralDetailsActivity
the UI always find the service and refresh, cannot click and trigger the listener on the characteristic list.

[suzp1984]

get it, the UI always to refresh. This is much more a UI design issue.
I will solve this after I have spare time.

[suzp1984]

oh, Another issue this CentralDetailsActivity:
No need following codes since it used ButterKnife View injection.

        mConnectionState = (TextView) findViewById(R.id.connection_state);
        mDataField = (TextView) findViewById(R.id.data_value);
        mRssiField = (TextView) findViewById(R.id.signal_rssi);