uru4000: fix cancelling of imaging from error callback
uru4000: fix cancelling of imaging from error callback

Call error callback before resetting img_transfer to NULL. This
variable is internally used to detect if we are still in imaging
loop and the call to execute_state_change() needs to be postponed.
Since this is the final thing imaging_complete() we can't reset
img_transfer until just before this call.

https://bugs.freedesktop.org/show_bug.cgi?id=57829

ccsystems/libfprint,anarsoul/libfprint,hyperair/fprint-bsapi,PDXostc/libfprint,ccsystems/libfprint,Gnate/libfprint,zOrg1331/libfprint,payden/libfprint,FabriceSalvaire/libfprint-baspi,jipumarino/libfprint,zemen/libfprint,freedesktop-unofficial-mirror/libfprint__libfprint,zemen/libfprint,abhishekgahlot/fprint-bsapi,jipumarino/libfprint,abhishekgahlot/fprint-bsapi,yingted/etes603,yingted/etes603,FabriceSalvaire/libfprint-baspi,FabriceSalvaire/libfprint-baspi,Gnate/libfprint,abhishekgahlot/libfprint,Gnate/libfprint,abhishekgahlot/libfprint,micw/libfprint,PDXostc/libfprint,micw/libfprint,PDXostc/libfprint,zemen/libfprint,rmarku/libfprint,abhishekgahlot/fprint-bsapi,zOrg1331/libfprint,jipumarino/libfprint,hyperair/fprint-bsapi,anarsoul/libfprint,zOrg1331/libfprint,sbambrough/libfprint_extended,rmarku/libfprint,sbambrough/libfprint_extended,freedesktop-unofficial-mirror/libfprint__libfprint,hyperair/fprint-bsapi,micw/libfprint,payden/libfprint,abhishekgahlot/libfprint,ccsystems/libfprint,yingted/etes603,rmarku/libfprint,iafilatov/libfprint,sbambrough/libfprint_extended,freedesktop-unofficial-mirror/libfprint__libfprint,payden/libfprint