patch 7.4.1137

Problem:    Illegal memory access when using :copen and :cclose.
Solution:   Avoid that curbuf is invalid. (suggestion by Justin M. Keyes)
            Add a test.

src/version.c

@@ -741,6 +741,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1137,
 /**/
     1136,
 /**/