patch 8.0.0229: local 'formatprg' option value leaks

Problem:    When freeing a buffer the local value of the 'formatprg' option is
            not cleared.
Solution:   Add missing change.
diff --git a/src/buffer.c b/src/buffer.c
index b79e277..b2c914d 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -2153,6 +2153,7 @@
 #if defined(FEAT_CRYPT)
     clear_string_option(&buf->b_p_cm);
 #endif
+    clear_string_option(&buf->b_p_fp);
 #if defined(FEAT_EVAL)
     clear_string_option(&buf->b_p_fex);
 #endif
diff --git a/src/version.c b/src/version.c
index 6d3b848..829b3b9 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    229,
+/**/
     228,
 /**/
     227,