RedfishClientPkg: fix access to unitialized variable.

It is possible that at the time of accessing to AsciiLocation pointer
the memory is not allocated.

Also gcc version 4.8.5 20150623 (Red Hat 4.8.5-44) emits a warning for
this case:

RedfishFeatureUtilityLib.c:1889:37: error: 'AsciiLocation' may be used uninitialized in this function [-Werror=maybe-uninitialized]
       *Location = StrAsciiToUnicode (AsciiLocation);

Cc: Igor Kulchytskyy <[email protected]>
Signed-off-by: Mike Maslenkin <[email protected]>
Reviewed-by: Nickle Wang <[email protected]>
Reviewed-by: Abner Chang <[email protected]>

RedfishClientPkg/Library/RedfishFeatureUtilityLib/RedfishFeatureUtilityLib.c

@@ -1856,7 +1856,8 @@ GetEtagAndLocation (
   }
 
   if (Location != NULL) {
-    *Location = NULL;
+    *Location     = NULL;
+    AsciiLocation = NULL;
 
     if (*(Response->StatusCode) == HTTP_STATUS_200_OK) {
       Header = HttpFindHeader (Response->HeaderCount, Response->Headers, HTTP_HEADER_LOCATION);