target/iscsi: Fix double free of a TUR followed by a solicited NOPOUT
Make sure all non-READ SCSI commands get targ_xfer_tag initialized
to 0xffffffff, not just WRITEs.
Double-free of a TUR cmd object occurs under the following scenario:
1. TUR received (targ_xfer_tag is uninitialized and left at 0)
2. TUR status sent
3. First unsolicited NOPIN is sent to initiator (gets targ_xfer_tag of 0)
4. NOPOUT for NOPIN (with TTT=0) arrives
- its ExpStatSN acks TUR status, TUR is queued for removal
- LIO tries to find NOPIN with TTT=0, but finds the same TUR instead,
TUR is queued for removal for the 2nd time