cros-sommelier: Rename --master to --parent

In line with go/coil.

This depends on the sommelier change in crrev.com/c/2580959 and as such
should only be submitted once we pass a milestone where that change is
present.

BUG=b:172846445
TEST=tbd

Change-Id: I32951d29c89bd1bc9c0908edb0c096ea16b55aef
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/containers/cros-container-guest-tools/+/2581098
Tested-by: Nic Hollingum <hollingum@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Fergus Dall <sidereal@google.com>
Reviewed-by: David Munro <davidmunro@google.com>
diff --git a/cros-sommelier/BUILD b/cros-sommelier/BUILD
index e12ef29..36fc45f 100644
--- a/cros-sommelier/BUILD
+++ b/cros-sommelier/BUILD
@@ -88,6 +88,6 @@
         "xkb-data",
     ],
     section = "misc",
-    version = "0.26",
+    version = "0.27",
     visibility = ["//cros-debs:__pkg__"],
 )
diff --git a/cros-sommelier/sommelier@.service b/cros-sommelier/sommelier@.service
index 50afdc7..4ef2cd9 100644
--- a/cros-sommelier/sommelier@.service
+++ b/cros-sommelier/sommelier@.service
@@ -1,5 +1,5 @@
 [Unit]
-Description=Master sommelier listening on socket wayland-%i
+Description=Parent sommelier listening on socket wayland-%i
 
 [Service]
 Environment="WAYLAND_DISPLAY_VAR=WAYLAND_DISPLAY"
@@ -11,7 +11,7 @@
                           SOMMELIER_DRM_DEVICE=/dev/dri/renderD128; \
                   /bin/true"
 ExecStart=/usr/bin/sommelier \
-              --master \
+              --parent \
               --sd-notify="READY=1" \
               --socket=wayland-%i \
               /bin/sh -c \