INCR-11 Unpin mailsnake and run make upgrade

requirements/edx/base.in

@@ -100,7 +100,7 @@ help-tokens
 html5lib                            # HTML parser, used for capa problems
 ipaddr==2.1.11                      # Ip network support for Embargo feature
 jsonfield                           # Django model field for validated JSON; used in several apps
-mailsnake==1.6.2                    # Needed for mailchimp (mailing djangoapp)
+mailsnake                           # Needed for mailchimp (mailing djangoapp)
 mako==1.0.2                         # Primary template language used for server-side page rendering
 Markdown                            # Convert text markup to HTML; used in capa problems, forums, and course wikis
 mongoengine==0.10.0                 # Object-document mapper for MongoDB, used in the LMS dashboard

requirements/edx/base.txt

@@ -160,7 +160,7 @@ lepl==5.1.3               # via rfc6266-parser
 libsass==0.10.0
 loremipsum==1.0.5
 lxml==3.8.0
-mailsnake==1.6.2
+mailsnake==1.6.4
 mako==1.0.2
 markdown==2.6.11
 markey==0.8               # via django-babel-underscore

requirements/edx/development.txt

@@ -202,7 +202,7 @@ libsass==0.10.0
 linecache2==1.0.0
 loremipsum==1.0.5
 lxml==3.8.0
-mailsnake==1.6.2
+mailsnake==1.6.4
 mako==1.0.2
 mando==0.6.4
 markdown==2.6.11

requirements/edx/testing.txt

@@ -195,7 +195,7 @@ libsass==0.10.0
 linecache2==1.0.0         # via traceback2
 loremipsum==1.0.5
 lxml==3.8.0
-mailsnake==1.6.2
+mailsnake==1.6.4
 mako==1.0.2
 mando==0.6.4              # via radon
 markdown==2.6.11