Fixed bug with native gem generation.
Fixed bug with native gem generation.

Task was inserting 'compile:mri' into gem_spec.files, causing the rubygems to complain that the file wasn't found.  Fixed by using ext_name instead of task prerequesites.

Signed-off-by: Alex Coles <60c6d277a8bd81de7fdde19201bf9c58a3df08f4@alexcolesportfolio.com>
simonkro/do_mysql,simonkro/do_mysql,simonkro/do_mysql