Fix handling of new mat_t variable in Mat_VarDelete
Fix handling of new mat_t variable in Mat_VarDelete

martinichka/matio-coder,CBL-ORION/matio-sf-mirror,tbeu/matio,MaartenBent/matio,tbeu/matio,CBL-ORION/matio-sf-mirror,MaartenBent/matio,tbeu/matio,CBL-ORION/matio,martinichka/matio-coder,MaartenBent/matio,martinichka/matio-coder,NJannasch/matio,telehan/libmatio,telehan/libmatio,tbeu/matio,NJannasch/matio,MaartenBent/matio,CBL-ORION/matio