InCallUI: Flip to Mute/Reject Call cleanup: fix ITelephony access

Using reflection to access ITelephony is a strange idea

Change-Id: Ia34b135460cc2b85fbd5db4585228a015c2a52b1
Merge pull request #1 from omnirom/android-4.4

InCallUI: Flip to Mute/Reject Call cleanup: fix ITelephony access