Modifying the report dates returns a 500 error [v5.5]

[orenyk]

Steps to replicate:

1. Visit reports index
2. Change start or end dates
3. Hit "Generate Report"

Expected: Report updates to match start and end dates
Actual: Nothing visibly changes, 500 error identified in Firebug

This is fairly important, let's get it fixed ASAP (worst case push v5.5.5 next week).

[orenyk]

Looks like this is literally a missing colon... we really need controller specs for this model (see #601); I'll try to implement those in the master branch (but will merge in the changes for release-v5.5 immediately so we can fix this in production).