SDK fix for MOBILE-2986, MOBSDK-766 & MOBSDK-769

The original workaround has been removed which does mean the "stream ... is sending an event before its open" warning now re-appears, some further investigation is required in this area, however, uploads do now succeed.

As well commenting out the original workaround in CMISHttpUploadRequest.m a couple of minor fixes were required in CMISAtomPubVersioningService.m, CMISPropertyDefinition.m and CMISTypeDefinition.m as highlighted by Xcode 6 compilation warnings.