Fixed several typos in the codebase

Change-Id: I66e05e8240cd24bc97a3591ba72023b23985f9c2
diff --git a/zuul/model.py b/zuul/model.py
index c5c5c7d..884ba09 100644
--- a/zuul/model.py
+++ b/zuul/model.py
@@ -287,7 +287,7 @@
 
 
 class ActionReporter(object):
-    """An ActionReporter has a reporter and its configured paramaters"""
+    """An ActionReporter has a reporter and its configured parameters"""
 
     def __repr__(self):
         return '<ActionReporter %s, %s>' % (self.reporter, self.params)