Bug 1411034 - Remove the const to fix the -Wignored-qualifiers warning r=mcmanus

MozReview-Commit-ID: AQ66p3bh9uX

--HG--
extra : rebase_source : 9196cfb334ec0cc303abcd1c04a2ddb4cd9cf15f

netwerk/cache/nsDiskCacheEntry.h

@@ -32,7 +32,7 @@ struct nsDiskCacheEntry {
                                     mKeySize + mMetaDataSize;
                               }
 
-    char*           Key()     { return reinterpret_cast<char*const>(this) +
+    char*           Key()     { return reinterpret_cast<char*>(this) +
                                     sizeof(nsDiskCacheEntry);
                               }