fixes "resiliencytest: resiliency process isn't OK if some promises fail"

Function should return True if everything is OK.
Also add some logging

slapos/resiliencytest/suites/resiliencytestsuite.py

@@ -201,6 +201,7 @@ class ResiliencyTestSuite(object):
     should make at least one of the promises complain.
     """
     for promise_directory in glob.glob('../*/etc/promise/'):
+      self.logger.info("Testing promises of instance's directory : %s", promise_directory)
       promise_list = os.listdir(promise_directory)
       for promise in promise_list:
         # XXX: for the moment ignore monitor promises as they can never succeed
@@ -213,6 +214,8 @@ class ResiliencyTestSuite(object):
           self.logger.error('ERROR : promise "%s" failed with output :\n%s', promise, e.output)
           return False
 
+    return True
+
   def runTestSuite(self):
     """
     Generate data to send,