Change https://github.com/edx/edx-platform/pull/8240 refactored the LTI
provider template rendering code and introduced an issue where a user was
required to be enrolled in a course before that course's content could be
accessed over LTI. According to the LTI design spec:
https://docs.google.com/document/d/185hdPvIxcKtiDOLjb4sTGovA_WYXWz5Cd79gCzQwBms
we delegate access control over LTI content to the LTI consumer, rather
than requiring that users enroll in edX courses explicitly (and that admins
keep edX and LTI provider enrollemnts consistent when students add or drop
courses).
This change fixes the immediate issue, which is disrupting the LTI Provider
pilot currently running at Harvard.
