fingerprint_viewer.xml: links to old screenshots removed.

app/src/main/res/values/fingerprint_viewer.xml

 <?xml version="1.0" encoding="utf-8"?>
 <resources>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_fingerprint_description">Your opponent can provide his fingerprint you can compare with specified here to be sure he is who you think he is. You should not use XMPP chat for this purpose.</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_is_verified">This contact is trusted</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_local_fingerprint">Your fingerprint:</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_remote_fingerprint">Your opponent\'s fingerprint:</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_scan_fingerprint">Scan QR code with opponent\'s fingerprint</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_show_fingerprint">Show QR code with your fingerprint</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint_play.png -->
     <string name="zxing_install_fail">There is no Google Play installed. Please install Barcode Scanner manually.</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint_scanner.png -->
     <string name="zxing_install_message">This application requires Barcode Scanner. Would you like to install it?</string>
-    <!-- http://dl.dropbox.com/u/1029995/com.xabber.android/otr_fingerprint.png -->
     <string name="otr_copy_fingerprint">Copy your fingerprint to clipboard</string>
 </resources>
\ No newline at end of file