Pin setuptools == 18.5
Pin setuptools == 18.5

Yesterday the new versions of setuptools (18.6 and 18.6.1) were released
where some functionality such as installation in the editable mode was
broken. It will be fixed in the 18.6.2 release.

Change-Id: Id19879c788efbba6c6e72fe6a4a97418df124525
Partial-Bug: #1519727

stackforge/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,huntxu/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,huntxu/fuel-web,eayunstack/fuel-web,stackforge/fuel-web,huntxu/fuel-web,huntxu/fuel-web,stackforge/fuel-web