toolchain-utils: change lease time limit for skylab

Currently we are leasing at most 10 hours for skylab DUTs, which could
not cover the run time nightly tests take on specific machines. We
temporarily increase this timeout so that skylab not release it before
we finishes the test.

BUG=chromium:1019439
TEST=None

Change-Id: I092159f48cebb17a3e130c580279422200d0fe01
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/toolchain-utils/+/1888298
Tested-by: Zhizhou Yang <zhizhouy@google.com>
Reviewed-by: Denis Nikitin <denik@chromium.org>
Commit-Queue: Zhizhou Yang <zhizhouy@google.com>
Auto-Submit: Zhizhou Yang <zhizhouy@google.com>
diff --git a/lock_machine.py b/lock_machine.py
index 40c7d8f..eca4bd5 100755
--- a/lock_machine.py
+++ b/lock_machine.py
@@ -69,7 +69,11 @@
   """
 
   SKYLAB_PATH = '/usr/local/bin/skylab'
-  LEASE_MINS = 600
+
+  # TODO(zhizhouy): lease time may needs to be dynamically adjusted. For now we
+  # set it long enough to cover the period to finish nightly rotation tests.
+  LEASE_MINS = 1440
+
   SKYLAB_CREDENTIAL = '/usr/local/google/home/mobiletc-prebuild' \
                       '/sheriff_utils/skylab_credential' \
                       '/chromeos-swarming-credential.json'