Corrected testing chef_gem syntax
Corrected testing chef_gem syntax

The `install_chef_gem_package` syntax is incorrect.  Corrected to
`install_chef_gem`.

ranjib/chefspec,jtimberman/chefspec,rsr5/chefspec,Thalagyrt/chefspec,lamont-granquist/chefspec,aspiers/chefspec,sethvargo/chefspec,mcoolive/chefspec,zuazo-forks/chefspec,bheuvel/chefspec,gsavage/chefspec,sethvargo/chefspec,shanethehat/chefspec,aspiers/chefspec,ranjib/chefspec,oldirty/chefspec,Thalagyrt/chefspec,375gnu/chefspec,shanethehat/chefspec,h4ck3rm1k3/chefspec,oldirty/chefspec,bheuvel/chefspec,gsavage/chefspec,jkeiser/chefspec,rsr5/chefspec,chefspec/chefspec,jkeiser/chefspec,coderanger/chefspec,chefspec/chefspec,lamont-granquist/chefspec,h4ck3rm1k3/chefspec,coderanger/chefspec,mcoolive/chefspec,375gnu/chefspec,jtimberman/chefspec