coisane: Fixed memory leak in case of unsupported option type

Reported by Coverity CID 85009.
winsane: Fixed memory leak after setting an option's string value

Reported by Coverity CID 84998.
winsane: Fixed memory leak in case of socket reconnect

Reported by Coverity CID 84997.
devsane: Fixed memory leak during creation of device install info

Reported by Coverity CID 84993.
winsane: Fixed socket leak in case of failure during initial connect

Reported by Coverity CID 84992.
wiasane: Fixed invalid memory access if plReceived param is NULL

Reported by Coverity CID 84985.
winsane: Fixed ignored result and logically dead code

Reported by Coverity CID 84984.
winsane: Fixed deleting void pointers with undefined behavior

delete_void: Operator 'delete', applied to void* argument value,
has undefined behavior, and most likely does not invoke the
object's destructor.

Reported by Coverity CID 84982, 84983, 84986, 84987, 84988 and 84989.