patch 8.0.1144: using wrong #ifdef for computing length

Problem:    Using wrong #ifdef for computing length.
Solution:   use BACKSLASH_IN_FILENAME instead of COLON_IN_FILENAME. (Yasuhiro
            Matsomoto, closes #2153)
diff --git a/src/version.c b/src/version.c
index 1eb93ef..5509b92 100644
--- a/src/version.c
+++ b/src/version.c
@@ -762,6 +762,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1144,
+/**/
     1143,
 /**/
     1142,