DRY up usage of rubygems_api_key.
DRY up usage of rubygems_api_key.

One can now override key name without monkey patching.

Signed-off-by: Nick Quaranto <75ef9faee755c70589550b513ad881e5a603182c@quaran.to>

alloy/gemcutter,1337807/rubygems.org,bpm/getbpm.org,square/rubygems.org,rubygems/rubygems.org-backup,rubygems/rubygems.org-backup,dstrctrng/private_event,1337807/rubygems.org,rubygems/rubygems.org-backup,dstrctrng/private_event,1337807/rubygems.org,square/rubygems.org,square/rubygems.org,alloy/gemcutter,bpm/getbpm.org