Fixes issue where byteCount of the disk cache being the wrong if the setObject:forKey methods are called for a key that already in the cache (i.e. updating the object for a key)
Fixes issue where byteCount of the disk cache being the wrong if the setObject:forKey methods are called for a key that already in the cache (i.e. updating the object for a key)

nguyehuuphuc08/TMCache,yimouleng/TMCache,Guicai-Li/TMCache,quanquan1986/TMCache,ondev/TMCache,libiao88/TMCache,yimouleng/TMCache,XZwalk/TMCache,tumblr/TMCache,nguyehuuphuc08/TMCache,ericzhou2008/TMCache,Suninus/TMCache,msdgwzhy6/TMCache,XZwalk/TMCache,ramoslin02/TMCache,ondev/TMCache,Guicai-Li/TMCache,tumblr/TMCache,libiao88/TMCache,ramoslin02/TMCache,Suninus/TMCache,quanquan1986/TMCache,msdgwzhy6/TMCache,ericzhou2008/TMCache