conman:  Don't log false "provisioning failed" messages.

Ratchets now have to be explicitly started, and are stopped upon
completion.  Ratchet checks won't fail unless the ratchet is active
(i.e. started and not stopped).

Change-Id: Ia01d45665d3e4d5ac4af7db36e9b20deb962572e
diff --git a/conman/connection_manager.py b/conman/connection_manager.py
index fb01acf..333e050 100755
--- a/conman/connection_manager.py
+++ b/conman/connection_manager.py
@@ -468,7 +468,6 @@
 
     for wifi in self.wifi:
       continue_wifi = False
-      provisioning_failed = self.provisioning_failed(wifi)
       if self.currently_provisioning(wifi):
         continue
 
@@ -960,6 +959,7 @@
       wifi.provisioning_ratchet.check()
       if wifi.provisioning_ratchet.done_after:
         wifi.status.provisioning_completed = True
+        wifi.provisioning_ratchet.stop()
         logging.info('%s successfully provisioned', wifi.name)
       return False
     except ratchet.TimeoutException:
diff --git a/conman/ratchet.py b/conman/ratchet.py
index 07e61a8..9c32ef2 100644
--- a/conman/ratchet.py
+++ b/conman/ratchet.py
@@ -146,6 +146,7 @@
 
   def reset(self):
     self._current_step = 0
+    self.active = False
     for step in self.steps:
       step.reset()
       self._set_step_status(step, False)
@@ -153,11 +154,18 @@
 
   def start(self):
     self.reset()
+    self.active = True
     self._set_current_step_status(True)
 
+  def stop(self):
+    self.active = False
+
   # Override check rather than evaluate because we don't want the Ratchet to
   # time out unless one of its steps does.
   def check(self):
+    if not self.active:
+      return
+
     if not self.done_after:
       while self.current_step().check():
         if not self.advance():
diff --git a/conman/ratchet_test.py b/conman/ratchet_test.py
index 97f7c94..79bdbfb 100755
--- a/conman/ratchet_test.py
+++ b/conman/ratchet_test.py
@@ -122,7 +122,7 @@
     wvtest.WVEXCEPT(ratchet.TimeoutException, r.check)
 
     x = y = z = 1
-    r.reset()
+    r.start()
     wvtest.WVPASS(r.check())
   finally:
     shutil.rmtree(status_export_path)