[autotest] only repair servo if the servo is required and in lab

Only raise exception if servo is required.

BUG=chromium:355824
TEST=None

Change-Id: I53ba122144b0f002fe1776361a160da95dd387c5
Reviewed-on: https://chromium-review.googlesource.com/191373
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
Tested-by: Dan Shi <dshi@chromium.org>
diff --git a/server/hosts/servo_host.py b/server/hosts/servo_host.py
index b0c8644..fbbbc36 100644
--- a/server/hosts/servo_host.py
+++ b/server/hosts/servo_host.py
@@ -121,10 +121,11 @@
         try:
             self.verify()
         except:
-            if required_by_test and self.is_in_lab():
-                self.repair_full()
-            else:
-                raise
+            if required_by_test:
+                if not self.is_in_lab():
+                    raise
+                else:
+                    self.repair_full()
 
 
     def is_in_lab(self):
@@ -593,4 +594,4 @@
     elif servo_args is not None:
         return ServoHost(required_by_test=True, is_in_lab=False, **servo_args)
     else:
-        return None
\ No newline at end of file
+        return None