MD Settings: remove --enable-md-settings until it's more important

MD Settings: remove --enable-md-settings until it's more important

Right now it just confuses folks trying to view chrome://md-settings.

We should re-add it when/if it actually changes what appears when
chrome://settings is navigated to.

R=orenb@chromium.org
BUG=425627
Committed: https://crrev.com/a6cd60f267272e2b988ca75647fbdc141376ce8a
Cr-Commit-Position: refs/heads/master@{#348826}

[Oren Blasberg, 2015-09-15 00:02:24]

lgtm

[Dan Beam, 2015-09-15 02:23:34]

The CQ bit was checked by dbeam@chromium.org

[Dan Beam, 2015-09-15 02:23:35]

The patchset sent to the CQ was uploaded after l-g-t-m from orenb@chromium.org
Link to the patchset: https://codereview.chromium.org/1336763011/#ps20001
(title: "also about:flags")

[commit-bot: I haz the power, 2015-09-15 02:23:42]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1336763011/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1336763011/20001

[commit-bot: I haz the power, 2015-09-15 02:56:03]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-09-15 02:56:38]

Patchset 2 (id:??) landed as
https://crrev.com/a6cd60f267272e2b988ca75647fbdc141376ce8a
Cr-Commit-Position: refs/heads/master@{#348826}

[commit-bot: I haz the power, 2015-09-23 12:42:04]

Patchset 2 (id:??) landed as
https://crrev.com/a6cd60f267272e2b988ca75647fbdc141376ce8a
Cr-Commit-Position: refs/heads/master@{#348826}