Refactoring code for issue #386, loop not needed
Keep default gh remote from being added each install command.

This started happening after my fix to #386, this didn't happen
before because the github remote was added to `conf` before
`saveConfig` was called. Since we are now waiting until each
package installs successfully, we can't just add github to
`conf.remotes` each time unless we want duplicates for each
`install` command.
Merge pull request #388 from CoryG89/master

Keep duplicate github remotes from being added to component.json