IMS: Notify supplementary service failed for call hold failures

- We need to notify supplementary service failed in case call
  hold fails.

BUG=26770582

Change-Id: Ie9855b35803c9f6dd8698dd9dc1fa7bb195989c0
diff --git a/res/values/strings.xml b/res/values/strings.xml
index d71025d..80c7e22 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -986,6 +986,8 @@
     <string name="incall_error_supp_service_reject">Can\'t reject call.</string>
     <!-- In-call screen: message displayed in an error dialog -->
     <string name="incall_error_supp_service_hangup">Can\'t release call(s).</string>
+    <!-- In-call screen: message displayed in an error dialog -->
+    <string name="incall_error_supp_service_hold">Can\'t hold calls.</string>
     <!-- In-call screen: call failure message displayed in an error dialog when WFC is enabled, is wifi-only, and not connected to a wireless network. [CHAR_LIMIT=NONE] -->
     <string name="incall_error_wfc_only_no_wireless_network">Connect to a wireless network to make a call.</string>