Merge branch 'nd/daemonize-gc' into maint

"git gc --auto" was recently changed to run in the background to
give control back early to the end-user sitting in front of the
terminal, but it forgot that housekeeping involving reflogs should
be done without other processes competing for accesses to the refs.

* nd/daemonize-gc:
gc --auto: do not lock refs in the background

diff --cc builtin/gc.c
index 85f5c2bc62ec1ead593f5aa2e3d7077e65f2f061,4588af70df9902f43b818d6ab107b47b0a282845..8d219d8c42cb4dfb64468f9b4d82648bff646685
--- 1/builtin/gc.c
--- 2/builtin/gc.c
+++ b/builtin/gc.c
@@@ -26,7 -26,7 +26,8 @@@ static const char * const builtin_gc_us
  };
  
  static int pack_refs = 1;
+ static int prune_reflogs = 1;
 +static int aggressive_depth = 250;
  static int aggressive_window = 250;
  static int gc_auto_threshold = 6700;
  static int gc_auto_pack_limit = 50;