Remove utils::TimeFromStructTimespec().

Use base::Time::FromTimeSpec() instead.

Test: mma
Change-Id: I0f2244b52188e8964a3eebc7f6188706105b850f
diff --git a/update_attempter.cc b/update_attempter.cc
index 5efd257..5f32312 100644
--- a/update_attempter.cc
+++ b/update_attempter.cc
@@ -225,7 +225,7 @@
     return;
   }
 
-  Time lsb_release_timestamp = utils::TimeFromStructTimespec(&sb.st_ctim);
+  Time lsb_release_timestamp = Time::FromTimeSpec(sb.st_ctim);
   Time now = system_state_->clock()->GetWallclockTime();
   TimeDelta age = now - lsb_release_timestamp;
   if (age.InSeconds() < 0) {