Increase duration timeout task manager

Sometimes, Jenkins or Travis is slow, and can't hit that 1 second timeout. This increases to 5 seconds to account for local slowness.

## Verification
 - [ ] Run `rspec --format=d spec/lib/msf/core/task_manager_spec.rb`
 - [ ] See success on, 'should handle task timeouts'

If you can figure out how to simulate a slow machine, feel free to post here.