patch 9.0.0552: crash when using NUL in buffer that uses :source

Problem:    Crash when using NUL in buffer that uses :source.
Solution:   Don't get a next line when skipping over NL.
diff --git a/src/version.c b/src/version.c
index c3b6c12..505185d 100644
--- a/src/version.c
+++ b/src/version.c
@@ -700,6 +700,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    552,
+/**/
     551,
 /**/
     550,