Relax redis dependency requirements and fix NPE in Redis tracing

Andrew Newdigaterequested to merge
an-relax-redis-requirements into master

Allow calling applications more flexibility on the version of redis-rb that they use.

Required for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/30238

This change also resolves a bug discovered when integrating this change into gitlab-ce, whereby some arguments appear to be nil, leading to NPEs in the application when tracing is enabled.

Edited by Andrew Newdigate

Merge request reports