audio: allow microphone access

- adds a NSMicrophoneUsageDescription key to the Info.plist file
  allowing use of the iphone's microphone

Change-Id: I4ff8e69f6aee5458053fcdaa1a7a5bbeeeb5ebf7
Reviewed-by: Kateryna Kostiuk <kateryna.kostiuk@savoirfairelinux.com>

Ring/Ring/Info.plist

@@ -57,6 +57,8 @@
 		<string>UIInterfaceOrientationLandscapeLeft</string>
 		<string>UIInterfaceOrientationLandscapeRight</string>
 	</array>
+	<key>NSMicrophoneUsageDescription</key>
+	<string>The microphone will be used for communication during a call.</string>
 	<key>UIViewControllerBasedStatusBarAppearance</key>
 	<false/>
 </dict>