[PVR] when a user set its own icon for the pvr logo, this one is reset to null  upon xbmc restart because UserSetIcon flag is not set
[PVR] if an user set icon does not exists anymore it will never be deleted from the database because updatefromclient do not check  user set icons.
[PVR] If a user set a custom name for the pvr channel, this name should be used too when searching icons
add a function IsIconExists in CPVRChannel and use it
typo &  cosmetics
remove unecessary check for empty path
remove unecessary force parameter in seticonpath