Updated SLAVE interface to Type 340 display to correct an obvious bug.

The value of the timeout was getting overwritten by incorrect code.
I was seeing timeout errors while trying to write to the display from
SHRDLU.  The fix seems to help a lot.

Author: eswenson1

src/l/slave.10 src/l/slave.11

@@ -146,8 +146,9 @@ DISLEEP:
 	MOVEI T,20.		;ELSE, NOSKIP AND LEAVE ERROR NUMBER IN A
 	SKIPL SIXOPD
 	 MOVEI T,100.		;FOR PDP10, WAIT UP TO 3.3 SECONDS
-DISLP3:	MOVEI T,1		;[FOR PDP6, UP TO .6 SECS] FOR SLAVE TO RESPOND
-	.SLEEP T,
+DISLP3:	
+	MOVEI D,1
+	.SLEEP D,		;[FOR PDP6, UP TO .6 SECS] FOR SLAVE TO RESPOND
 	SKIPE A,ERRLOC
 DISLP4:	 SOSA (P)
 	  SKIPN DFUNCTION