patch 9.0.1666: compiler may warn for uninitialized variable

Problem:    Compiler may warn for uninitialized variable.
Solution:   Initialize this_props_len. (Christian Brabandt, closes #12599)

Author: chrisbra

src/memline.c

@@ -3626,7 +3626,7 @@ adjust_text_props_for_delete(
     int		idx;
     int		line_start;
     long	line_size;
-    int		this_props_len;
+    int		this_props_len = 0;
     char_u	*text;
     size_t	textlen;
     int		found;

src/version.c

@@ -695,6 +695,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1666,
 /**/
     1665,
 /**/