patch 9.1.0458: Coverity complains about division by zero

Problem:  Coverity complains about division by zero
Solution: Check explicitly for sw_val being zero

Shouldn't happen, since tabstop value should always be larger than zero.
So just add this as a safety measure.

Signed-off-by: Christian Brabandt <cb@256bit.org>

src/ops.c

@@ -233,6 +233,9 @@ shift_line(
     int		i, j;
     int		sw_val = trim_to_int(get_sw_value_indent(curbuf, left));
 
+    if (sw_val == 0)
+	sw_val = 1;		// shouldn't happen, just in case
+
     count = get_indent();	// get current indent
 
     if (round)			// round off indent

src/version.c

@@ -704,6 +704,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    458,
 /**/
     457,
 /**/