Merged in [17794] from mark@painless-security.com:

Add the 'msg' variable for interpolation on reviewer availability change emails, and reformat the add-a-period email.  Fixes #2891.
 - Legacy-Id: 17799
Note: SVN reference [17794] has been migrated to Git commit 96bc71f51f150cec7043aca60d0156d35847019b

ietf/group/views.py

@@ -1797,7 +1797,7 @@ def change_reviewer_settings(request, acronym, reviewer_email, group_type=None):
             in_the_past = period.end_date and period.end_date < today
 
             if not in_the_past:
-                msg = "Unavailable for review: {} - {} ({})  {}".format(
+                msg = "{} -- {} {}\n                         {}".format(
                     period.start_date.isoformat() if period.start_date else "indefinite",
                     period.end_date.isoformat() if period.end_date else "indefinite",
                     period.get_availability_display(),

ietf/review/utils.py

@@ -360,6 +360,7 @@ def email_reviewer_availability_change(request, team, reviewer_role, msg, by):
             "reviewer_overview_url": url,
             "reviewer": reviewer_role.person,
             "team": team,
+            "msg": msg,
             "by": by,
         }, cc=cc)