Fix :param: in docstring

In docstring :param should be used instead of :param:.

Change-Id: I48b6e35c5835eb06638c31b9ad2de1801ef5dfd2

cinder/context.py

@@ -195,7 +195,7 @@ class RequestContext(context.RequestContext):
             location of the object e.g. ``{'project_id': context.project_id}``.
             If None, then this default target will be considered:
             {'project_id': self.project_id, 'user_id': self.user_id}
-        :param: target_obj: dictionary representing the object which will be
+        :param target_obj: dictionary representing the object which will be
             used to update target.
         :param fatal: if False, will return False when an
             exception.PolicyNotAuthorized occurs.

cinder/volume/drivers/dell_emc/powermax/rest.py

@@ -1699,7 +1699,7 @@ class PowerMaxRest(object):
            "snapVxCapable": true,
            "rdfCapable": true}
 
-        :param: array
+        :param array
         :returns: capabilities dict for the given array
         """
         array_capabilities = None

cinder/volume/drivers/remotefs.py

@@ -838,8 +838,8 @@ class RemoteFSSnapDriverBase(RemoteFSDriver):
     def _read_info_file(self, info_path, empty_if_missing=False):
         """Return dict of snapshot information.
 
-           :param: info_path: path to file
-           :param: empty_if_missing: True=return empty dict if no file
+           :param info_path: path to file
+           :param empty_if_missing: True=return empty dict if no file
         """
 
         if not os.path.exists(info_path):