patch 8.0.0851: 'smartindent' is used even when 'indentexpr' is set

Problem:    'smartindent' is used even when 'indentexpr' is set.
Solution:   Ignore 'smartindent' when 'indentexpr' is set. (Hirohito Higashi)
diff --git a/src/misc1.c b/src/misc1.c
index 4f33015..f19c2dc 100644
--- a/src/misc1.c
+++ b/src/misc1.c
@@ -627,6 +627,9 @@
 # ifdef FEAT_CINDENT
 					&& !curbuf->b_p_cin
 # endif
+# ifdef FEAT_EVAL
+					&& *curbuf->b_p_inde == NUL
+# endif
 			);
     int		no_si = FALSE;		/* reset did_si afterwards */
     int		first_char = NUL;	/* init for GCC */