Order of s.add_dependency is important

if s.add_dependency "mime-types", "~> 1.16" is specified below fog, gem considers fog first and its requirement on mime-types > 0, pulls in mime-types 2.0.  I gave gem too much credit for calculating dependencies ordering, it does _not_ do that at all.
Merge pull request #877 from braddeicide/master

Order of add_dependency is important, mail-types must come before fog.