Rename SEGMENT_KEY to have a unique key name for both CMS and LMS

common/djangoapps/student/models.py

@@ -1052,7 +1052,7 @@ class CourseEnrollment(models.Model):
             with tracker.get_tracker().context(event_name, context):
                 tracker.emit(event_name, data)
 
-                if settings.SEGMENT_KEY:
+                if hasattr(settings, 'LMS_SEGMENT_KEY') and settings.LMS_SEGMENT_KEY:
                     tracking_context = tracker.get_tracker().resolve_context()
                     analytics.track(self.user_id, event_name, {
                         'category': 'conversion',

common/djangoapps/student/views.py

@@ -1163,7 +1163,7 @@ def login_user(request, error=""):  # pylint: disable=too-many-statements,unused
         LoginFailures.clear_lockout_counter(user)
 
     # Track the user's sign in
-    if settings.SEGMENT_KEY:
+    if hasattr(settings, 'LMS_SEGMENT_KEY') and settings.LMS_SEGMENT_KEY:
         tracking_context = tracker.get_tracker().resolve_context()
         analytics.identify(user.id, {
             'email': email,
@@ -1601,7 +1601,7 @@ def create_account_with_params(request, params):
         third_party_provider = provider.Registry.get_from_pipeline(running_pipeline)
 
     # Track the user's registration
-    if settings.SEGMENT_KEY:
+    if hasattr(settings, 'LMS_SEGMENT_KEY') and settings.LMS_SEGMENT_KEY:
         tracking_context = tracker.get_tracker().resolve_context()
         identity_args = [
             user.id,  # pylint: disable=no-member