Fix left nav for Aura Docs

Left nav broke after commit 2037c31ddc81eae3edaf6ddd5bcfd0009fefe1bd.

Not sure why, but this workaround will unblock other Aura developers that need the
reference tab of Aura Docs.

@rev goliver@
Merging origin/tbliss/master-pending-auradocs-fix into master