Change logging to syslog; fix CRD in Yosemite

Change logging to use syslog; fix CRD in Yosemite

Have the Chromoting host write logs to syslog. This works around the
issue where, in some Yosemite configurations, launchd fails to start the
agent if the user running the agent does not have write access to the
log or the log's directory.

Logging to syslog has additional advantages such as:
- Log rotation and overflow are now managed by the system.
- Messages are read-restricted to the user running the agent.

After this change, logs will no longer be stored in
/var/log/org.chromium.chromoting.log. To obtain logs, use the following
command:

sudo syslog -k Facility org.chromium.chromoting

If 'sudo' is omitted, messages logged in the login screen (while the
agent is running as root) will not be available.

N.B. The changes to ChromotingHostService.pkgproj were made using the 'Packages'
program. To test the changes, I built and installed a .dmg from scratch.

BUG=468121
Committed: https://crrev.com/25cef11863014bc8ff4a8ff16d8570ad9c62bedc
Cr-Commit-Position: refs/heads/master@{#324550}

[dcaiafa, 2015-04-09 19:47:00]

dcaiafa@chromium.org changed reviewers:
+ jamiewalch@chromium.org

[dcaiafa, 2015-04-09 19:47:00]

ptal

[Jamie, 2015-04-09 23:12:04]

lgtm

[Jamie, 2015-04-09 23:13:11]

Please update the wiki instructions on log gathering to include information on
how to use this new method.

[dcaiafa, 2015-04-09 23:46:32]

The CQ bit was checked by dcaiafa@chromium.org

[commit-bot: I haz the power, 2015-04-09 23:49:00]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1073883002/1

[dcaiafa, 2015-04-10 00:11:03]

On 2015/04/09 23:13:11, Jamie wrote:
> Please update the wiki instructions on log gathering to include information on
> how to use this new method.

Done.

[commit-bot: I haz the power, 2015-04-10 01:07:16]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-10 01:08:54]

Patchset 1 (id:??) landed as
https://crrev.com/25cef11863014bc8ff4a8ff16d8570ad9c62bedc
Cr-Commit-Position: refs/heads/master@{#324550}