Don't send terminal response without cmd details.

bug:6481578
Change-Id: Ie9f6e33c49307ddd884015a400f90e5477cc551e

Author: John Wang

telephony/java/com/android/internal/telephony/cat/CatService.java

@@ -169,8 +169,11 @@ private void handleRilMsg(RilMessage rilMsg) {
             } catch (ClassCastException e) {
                 // for error handling : cast exception
                 CatLog.d(this, "Fail to parse proactive command");
-                sendTerminalResponse(mCurrntCmd.mCmdDet, ResultCode.CMD_DATA_NOT_UNDERSTOOD,
+                // Don't send Terminal Resp if command detail is not available
+                if (mCurrntCmd != null) {
+                    sendTerminalResponse(mCurrntCmd.mCmdDet, ResultCode.CMD_DATA_NOT_UNDERSTOOD,
                                      false, 0x00, null);
+                }
                 break;
             }
             if (cmdParams != null) {