Added python-heatclient back to requirements.txt
Fixed indentation bug in Racks controller
Blank line fixes related to previous regressions

There were 3 wrongly indented return statements introduced in pep8
pull request [1], then they were fixed again but they were still
missing the blank lines that caused pblaho's autoindenter to indent
the return statements wrong. This commit adds those blank lines.

[1] https://github.com/tuskar/tuskar/pull/52