Adds instagram and removes google-plus footer links

PROD-1178

lms/djangoapps/branding/tests/test_api.py

@@ -148,8 +148,8 @@ class TestFooter(TestCase):
                  'icon-class': 'fa-twitter-square', 'title': 'Twitter'},
                 {'url': '#', 'action': 'Follow \xe9dX on LinkedIn', 'name': 'linkedin',
                  'icon-class': 'fa-linkedin-square', 'title': 'LinkedIn'},
-                {'url': '#', 'action': 'Follow \xe9dX on Google+', 'name': 'google_plus',
-                 'icon-class': 'fa-google-plus-square', 'title': 'Google+'},
+                {'url': '#', 'action': 'Follow \xe9dX on Instagram', 'name': 'instagram',
+                 'icon-class': 'fa-instagram', 'title': 'Instagram'},
                 {'url': '#', 'action': 'Subscribe to the \xe9dX subreddit',
                  'name': 'reddit', 'icon-class': 'fa-reddit-square', 'title': 'Reddit'}
             ],

lms/djangoapps/courseware/tests/test_footer.py

@@ -22,7 +22,7 @@ class TestFooter(TestCase):
 
     SOCIAL_MEDIA_NAMES = [
         "facebook",
-        "google_plus",
+        "instagram",
         "twitter",
         "linkedin",
         "tumblr",
@@ -33,7 +33,7 @@ class TestFooter(TestCase):
 
     SOCIAL_MEDIA_URLS = {
         "facebook": "http://www.facebook.com/",
-        "google_plus": "https://plus.google.com/",
+        "instagram": "https://instagram.com/",
         "twitter": "https://twitter.com/",
         "linkedin": "http://www.linkedin.com/",
         "tumblr": "http://www.tumblr.com/",

lms/envs/common.py

@@ -2599,7 +2599,7 @@ SOCIAL_MEDIA_FOOTER_NAMES = [
     "twitter",
     # "youtube", see PROD-816 for more details
     "linkedin",
-    "google_plus",
+    "instagram",
     "reddit",
 ]
 
@@ -2631,12 +2631,12 @@ SOCIAL_MEDIA_FOOTER_DISPLAY = {
         "icon": "fa-linkedin-square",
         "action": _(u"Follow {platform_name} on LinkedIn")
     },
-    "google_plus": {
-        # Translators: This is the website name of plus.google.com.  Please
-        # translate this the way that Google+ advertises in your language.
-        "title": _("Google+"),
-        "icon": "fa-google-plus-square",
-        "action": _(u"Follow {platform_name} on Google+")
+    "instagram": {
+        # Translators: This is the website name of www.instagram.com.  Please
+        # translate this the way that Instagram advertises in your language.
+        "title": _("Instagram"),
+        "icon": "fa-instagram",
+        "action": _(u"Follow {platform_name} on Instagram")
     },
     "tumblr": {
         # Translators: This is the website name of www.tumblr.com.  Please