[iOS] Update log to indicate dependency on iOS 7
[iOS] Update log to indicate dependency on iOS 7

Address issue #780: iOS 6 issues with blocks when using 2.0+
paulbatum/azure-mobile-services,dhei/azure-mobile-services,shrishrirang/azure-mobile-services,yuqiqian/azure-mobile-services,dhei/azure-mobile-services,intellitour/azure-mobile-services,shrishrirang/azure-mobile-services,gb92/azure-mobile-services,soninaren/azure-mobile-services,shrishrirang/azure-mobile-services,jeremy50dj/azure-mobile-services,YOTOV-LIMITED/azure-mobile-services,intellitour/azure-mobile-services,fabiocav/azure-mobile-services,soninaren/azure-mobile-services,Azure/azure-mobile-services,soninaren/azure-mobile-services,soninaren/azure-mobile-services,shrishrirang/azure-mobile-services,jeremy50dj/azure-mobile-services,pragnagopa/azure-mobile-services,Reminouche/azure-mobile-services,yuqiqian/azure-mobile-services,paulbatum/azure-mobile-services,dcristoloveanu/azure-mobile-services,paulbatum/azure-mobile-services,intellitour/azure-mobile-services,Reminouche/azure-mobile-services,YOTOV-LIMITED/azure-mobile-services,soninaren/azure-mobile-services,paulbatum/azure-mobile-services,pragnagopa/azure-mobile-services,yuqiqian/azure-mobile-services,dhei/azure-mobile-services,YOTOV-LIMITED/azure-mobile-services,fabiocav/azure-mobile-services,Reminouche/azure-mobile-services,soninaren/azure-mobile-services,jeremy50dj/azure-mobile-services,intellitour/azure-mobile-services,pragnagopa/azure-mobile-services,Azure/azure-mobile-services,gb92/azure-mobile-services,dhei/azure-mobile-services,shrishrirang/azure-mobile-services,Azure/azure-mobile-services,dcristoloveanu/azure-mobile-services,intellitour/azure-mobile-services,jeremy50dj/azure-mobile-services,shrishrirang/azure-mobile-services,yuqiqian/azure-mobile-services,Azure/azure-mobile-services,YOTOV-LIMITED/azure-mobile-services,YOTOV-LIMITED/azure-mobile-services,Azure/azure-mobile-services,dcristoloveanu/azure-mobile-services,Reminouche/azure-mobile-services,yuqiqian/azure-mobile-services,fabiocav/azure-mobile-services,fabiocav/azure-mobile-services,intellitour/azure-mobile-services,pragnagopa/azure-mobile-services,pragnagopa/azure-mobile-services,jeremy50dj/azure-mobile-services,fabiocav/azure-mobile-services,Azure/azure-mobile-services,paulbatum/azure-mobile-services,dcristoloveanu/azure-mobile-services,pragnagopa/azure-mobile-services,gb92/azure-mobile-services,YOTOV-LIMITED/azure-mobile-services,gb92/azure-mobile-services,paulbatum/azure-mobile-services,gb92/azure-mobile-services,jeremy50dj/azure-mobile-services,dcristoloveanu/azure-mobile-services,yuqiqian/azure-mobile-services,gb92/azure-mobile-services,Reminouche/azure-mobile-services,fabiocav/azure-mobile-services,Reminouche/azure-mobile-services,dhei/azure-mobile-services,dcristoloveanu/azure-mobile-services