Remove Servo.recovery_supported() and related code.

The method is no longer relevant, as it always returns True, and
there are no callers.

BUG=None
TEST=None

Change-Id: I9b0d7cde4d1499b49b841eb8cf9d944eb97c3bf7
Reviewed-on: https://chromium-review.googlesource.com/203625
Reviewed-by: Dan Shi <dshi@chromium.org>
Commit-Queue: Richard Barnette <jrbarnette@chromium.org>
Tested-by: Richard Barnette <jrbarnette@chromium.org>
diff --git a/server/cros/servo/servo.py b/server/cros/servo/servo.py
index f59a88e..f676930 100644
--- a/server/cros/servo/servo.py
+++ b/server/cros/servo/servo.py
@@ -70,15 +70,6 @@
                                  'sleep:%.4f' % self._RESET_HOLD_TIME,
                                  'warm_reset:off'])
 
-    def recovery_supported(self):
-        """Return whether the power on/off methods are supported.
-
-        @return True means the power_on() and power_off() methods will
-                not raise a NotImplementedError.  False means they will.
-
-        """
-        return True
-
     def power_off(self):
         """Force the DUT to power off.
 
@@ -539,21 +530,6 @@
             return None
 
 
-    def recovery_supported(self):
-        """Return whether servo-based recovery should work.
-
-        Use of `image_to_servo_usb()` and `install_recovery_image()`
-        relies on DUT-board specific behaviors, and is not supported
-        for all types of board.  Return whether these two operations
-        are expected to succeed for the current DUT.
-
-        @return `True` iff the recovery related methods are supported
-                for this servo and DUT.
-
-        """
-        return self._power_state.recovery_supported()
-
-
     def image_to_servo_usb(self, image_path=None,
                            make_image_noninteractive=False):
         """Install an image to the USB key plugged into the servo.