fsogsmd: muxtransport: don't close a channel that has never been opened
fsogsmd: muxtransport: don't close a channel that has never been opened

slyon/debian-fso-deviced,slyon/debian-libfsoframework,slyon/debian-fso-deviced,slyon/debian-libfsoframework,slyon/debian-fso-usaged,slyon/debian-fso-usaged