Address compiler warning

[ Merge of http://go/wvgerrit/14788 ]

A retired error code was not being handled when converting from
a WVStatus error code to a ERROR_DRM_VENDOR error code.

b/13976775

Change-Id: Ib4363792e4a5e9a20fc718d169b3e0348413267a

libwvdrmengine/include/mapErrors-inl.h

@@ -343,6 +343,8 @@ static android::status_t mapCdmResponseType(wvcdm::CdmResponseType res) {
       return kEmptyLicenseRequest;
     case wvcdm::UNKNOWN_ERROR:
       return android::ERROR_DRM_UNKNOWN;
+    case wvcdm::UNUSED_1:
+      return android::UNKNOWN_ERROR;
   }
 
   // Return here instead of as a default case so that the compiler will warn