scsi_transport_iscsi: return -EOVERFLOW for Too many iscsi targets

setting err as -EOVERFLOW for Too many iscsi targets.

Also fixes a spurious compiler warning for gcc 4.3.3 and gcc 4.4 :

CC drivers/scsi/scsi_transport_iscsi.o
drivers/scsi/scsi_transport_iscsi.c: In function ‘iscsi_add_session’:
drivers/scsi/scsi_transport_iscsi.c:678: warning: ‘err’ may be used uninitialized in this function

Signed-off-by: Jaswinder Singh Rajput <[e-mail]>
Acked-by: Mike Christie <[e-mail]>
Signed-off-by: James Bottomley <[e-mail]>

drivers/scsi/scsi_transport_iscsi.c

···
 						 "Too many iscsi targets. Max "
 						 "number of targets is %d.\n",
 						 ISCSI_MAX_TARGET - 1);
+			err = -EOVERFLOW;
 			goto release_host;
 		}
 	}