[autotest] Remove the concept of 'protection level' from repair.

In original Autotest, hosts have a 'protection level' that is
passed to repair jobs in order to limit the specific kinds of repair
that can be done.  For the CrOS lab, this concept is largely not
useful; we want a uniform repair procedure determined by the kind of
DUT being repaired, not by a database configuration.

This removes the concept of 'protection level' from the repair flow;
repair steps are now determined only by the class of Host that
handles the operation.  The protection level remains in the
database, but the only meaningful value is 'Do not verify'.  That
setting on a host will prevent it from running any verify, cleanup,
or repair tasks.  This is done for the sake of non-DUT hosts that
exist in the CrOS lab AFE database.

BUG=None
TEST=unit tests, and run repair in a local instance

Change-Id: I1d512eb2b1fe604b70fec00b3a290f5f6b9d9beb
Reviewed-on: https://chromium-review.googlesource.com/312979
Commit-Ready: Richard Barnette <jrbarnette@chromium.org>
Tested-by: Richard Barnette <jrbarnette@chromium.org>
Reviewed-by: Dan Shi <dshi@chromium.org>
diff --git a/server/hosts/servo_host.py b/server/hosts/servo_host.py
index c4f1eb0..79d05ec 100644
--- a/server/hosts/servo_host.py
+++ b/server/hosts/servo_host.py
@@ -140,7 +140,7 @@
                 if not self.is_in_lab():
                     raise
                 else:
-                    self.repair_full()
+                    self.repair()
 
 
     def is_in_lab(self):
@@ -591,7 +591,7 @@
         time.sleep(self.REBOOT_DELAY_SECS)
 
 
-    def repair_full(self):
+    def repair(self):
         """Attempt to repair servo host.
 
         This overrides the base class function for repair.