Zed update through "Graceful shutdown with SIGTERM" by mattnibs

This is an auto-generated commit with a Zed dependency update. The Zed PR
brimdata/super#2737, authored by @mattnibs,
has been merged.

Graceful shutdown with SIGTERM

go.mod

@@ -3,7 +3,7 @@ module github.com/brimdata/brimcap
 go 1.16
 
 require (
-	github.com/brimdata/zed v0.29.1-0.20210517234642-1d16c1b6ae24
+	github.com/brimdata/zed v0.29.1-0.20210519174021-7c92f41f09b7
 	github.com/fsnotify/fsnotify v1.4.9
 	github.com/golang/mock v1.5.0
 	github.com/google/gopacket v1.1.19

go.sum

@@ -18,8 +18,8 @@ github.com/axiomhq/hyperloglog v0.0.0-20191112132149-a4c4c47bc57f/go.mod h1:2stg
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1/go.mod h1:G2ZrVWU2WbWT9wwq4/hrbKbnv/1ERSJQ0ibhJ6rlkpw=
-github.com/brimdata/zed v0.29.1-0.20210517234642-1d16c1b6ae24 h1:+01D81QGdx9Tzclqdw/F5YASWApi2MaUM+5tTXM+Q60=
-github.com/brimdata/zed v0.29.1-0.20210517234642-1d16c1b6ae24/go.mod h1:qfj6p4h0TQIyKtyuqltO3jneIUP6C1hRS5THEul7Rls=
+github.com/brimdata/zed v0.29.1-0.20210519174021-7c92f41f09b7 h1:vpfeQrY2v6g+Q8e7Wo9JqPWEsazf9xT9E1YUT06E3Zc=
+github.com/brimdata/zed v0.29.1-0.20210519174021-7c92f41f09b7/go.mod h1:qfj6p4h0TQIyKtyuqltO3jneIUP6C1hRS5THEul7Rls=
 github.com/cespare/xxhash v1.1.0/go.mod h1:XrSqR1VqqWfGrhpAt58auRo0WTKS1nRRg3ghfAqPWnc=
 github.com/cespare/xxhash/v2 v2.1.1/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XLFGgcrjCOs=
 github.com/coreos/etcd v3.3.10+incompatible/go.mod h1:uF7uidLiAD3TWHmW31ZFd/JWoc32PjwdhPthX9715RE=