Crespo4G: Voicemail: Add 'config_telephony_...' for Sprint

'*86' which is set now as a default at CDMAPhone.java,
is default voicemail number for Verizon.
For Sprint, we use user's own number for voicemail.

So we add codes in CDMAPhone.java to use
'config_telephony_use_own_number_for_voicemail',
and use config.xml to set this value as false.
Then we overlay Sprint's own config.xml file to
override 'config_telephony_use_own_number_for_voicemail' as a true.

Change-Id: I110914bdfa9a79aaba89d3b80edbcf044e9aabee

Author: Samyeoul Choi

core/res/res/values/config.xml

@@ -377,4 +377,7 @@
     <!-- Do not translate. Defines the slots is Two Digit Number for dialing normally not USSD -->
     <string-array name="config_twoDigitNumberPattern">
     </string-array>
+
+    <!-- The VoiceMail default value is displayed to my own number if it is true -->
+    <bool name="config_telephony_use_own_number_for_voicemail">false</bool>
 </resources>

telephony/java/com/android/internal/telephony/cdma/CDMAPhone.java

@@ -730,7 +730,14 @@ public String getVoiceMailNumber() {
         String number = null;
         SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(getContext());
         // TODO: The default value of voicemail number should be read from a system property
-        number = sp.getString(VM_NUMBER_CDMA, "*86");
+
+        // Read platform settings for dynamic voicemail number
+        if (getContext().getResources().getBoolean(com.android.internal
+                .R.bool.config_telephony_use_own_number_for_voicemail)) {
+            number = sp.getString(VM_NUMBER_CDMA, getLine1Number());
+        } else {
+            number = sp.getString(VM_NUMBER_CDMA, "*86");
+        }
         return number;
     }