[PATCH 13/16] packfile: ensure `close_pack_revindex()` frees in-memory revindex

[Taylor Blau <me@ttaylorr.com>]

The following commit will introduce a case where we write a MIDX bitmap
over packs that do not themselves have on-disk *.rev files.

This case is supported within Git, and we will simply fall back to
generating the revindex in memory. But we don't ever release that
memory, causing a leak that is exposed by a test introduced in the
following commit.

(As far as I could find, we never free()'d memory allocated as a
byproduct of creating an in-memory revindex, likely because that code
predates the leak-checking niceties we have in the test suite now.)

Rectify this by calling `FREE_AND_NULL()` on the `p->revindex` field
when calling `close_pack_revindex()`.

Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
 packfile.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/packfile.c b/packfile.c
index d4de9f3ffe8..97f7662e079 100644
--- a/packfile.c
+++ b/packfile.c
@@ -420,6 +420,8 @@ void close_pack_index(struct packed_git *p)
 
 static void close_pack_revindex(struct packed_git *p)
 {
+	FREE_AND_NULL(p->revindex);
+
 	if (!p->revindex_map)
 		return;
 
-- 
2.53.0.729.g817728289e1.dirty