Fixed STR sequence termination condition

ascii code may only be checked for characters that have length equal to
1, not width equal to 1

st.c

@@ -2663,7 +2663,7 @@ tputc(char *c, int len) {
 	 * character.
 	 */
 	if(term.esc & ESC_STR) {
-		if(width == 1 &&
+		if(len == 1 &&
 		   (ascii == '\a' || ascii == 030 ||
 		    ascii == 032  || ascii == 033 ||
 		    ISCONTROLC1(unicodep))) {