Remove "import lock_machine".

We do not have this file any longer, remove it. Rahul and I are having
problem running crosperf because of this.

TEST=run crosperf successfully
BUG=None

Change-Id: I396d30e6bb2362db99f9b16095ef862a1ab417f5
Reviewed-on: https://chrome-internal-review.googlesource.com/219770
Reviewed-by: Caroline Tice <cmtice@google.com>
Commit-Queue: Han Shen <shenhan@google.com>
Tested-by: Han Shen <shenhan@google.com>
diff --git a/crosperf/settings_factory.py b/crosperf/settings_factory.py
index 96e8d90..ba21a64 100644
--- a/crosperf/settings_factory.py
+++ b/crosperf/settings_factory.py
@@ -6,8 +6,6 @@
 
 """Setting files for global, benchmark and labels."""
 
-import lock_machine
-
 from field import BooleanField
 from field import FloatField
 from field import IntegerField