Use REPO_URL constant for gemspec homepage
Use REPO_URL constant for gemspec homepage

This reduces code duplication.

Change-Id: Id32cbee7b265939ff3477c07d65192fc860aa0f3
Reviewed-on: http://gerrit.causes.com/35622
Reviewed-by: Shane da Silva <6f6e68d1df92f30cb4b3ce35260ddf94a402f33d@causes.com>
Tested-by: Shane da Silva <6f6e68d1df92f30cb4b3ce35260ddf94a402f33d@causes.com>

blech75/overcommit,TheSooth/overcommit,blech75/overcommit,oxocode/overcommit,gnagel/overcommit,gnagel/overcommit,oxocode/overcommit,TheSooth/overcommit