patch 9.1.1481: gcc complains about uninitialized variable

Problem:  gcc complains about uninitialized variable
          (Tony Mechelynck, after v9.1.1476)
Solution: initialize variable

Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/src/ex_cmds.c b/src/ex_cmds.c
index c4a86c9..5d9b722 100644
--- a/src/ex_cmds.c
+++ b/src/ex_cmds.c
@@ -656,7 +656,7 @@
     linenr_T	count = eap->line2 - eap->line1 + 1;
     char_u	*p;
     char_u	*s;
-    char_u	save_c;			// temporary character storage
+    char_u	save_c = 0;		// temporary character storage
     int		keep_only_unique = FALSE;
     int		keep_only_not_unique = eap->forceit ? TRUE : FALSE;
     long	deleted = 0;