patch 8.2.2730: Coverity complains about not restoring character

Problem:    Coverity complains about not restoring character.
Solution:   Also restore the character in case of an error.

src/version.c

@@ -750,6 +750,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    2730,
 /**/
     2729,
 /**/

src/vim9compile.c

@@ -6108,6 +6108,7 @@ compile_load_lhs(
 	{
 	    // this should not happen
 	    emsg(_(e_missbrac));
+	    var_start[varlen] = c;
 	    return FAIL;
 	}
 	var_start[varlen] = c;