Make new baremetal trybots receive tryjobs by default.

I've done several green builds with these machines, but I suspect
some of the flakiness we still see in the build waterfall may
occur on these ones. Hopefully at least the ones for vie_auto_test
will be ironed out in Q1 as the old Video Engine API becomes deprecated.

TEST=none
BUG=chromium:332726
R=tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/7459004

git-svn-id: http://webrtc.googlecode.com/svn/trunk@5414 4adac7df-926f-26a2-2b94-8c16560cd09d

PRESUBMIT.py

@@ -170,6 +170,7 @@ def GetPreferredTrySlaves(project, change):
   linux_bots = [
       'linux',
       'linux_asan',
+      'linux_baremetal',
       'linux_memcheck',
       'linux_rel',
       'linux_tsan',
@@ -177,11 +178,13 @@ def GetPreferredTrySlaves(project, change):
   mac_bots = [
       'mac',
       'mac_asan',
+      'mac_baremetal',
       'mac_rel',
       'mac_x64_rel',
   ]
   win_bots = [
       'win',
+      'win_baremetal',
       'win_rel',
       'win_x64_rel',
   ]