portageq get_repos: fix <eroot> parameter (bug 670082)

Use the @uses_configroot decorator to make portage get_repos
respect the <eroot> parameter, like portage repos_config since
commit 382f4be415394886026ccd5dcd08ca96ecda31fa. Apply the same
fix to master_repositories and master_repos.

Bug: https://bugs.gentoo.org/670082
Signed-off-by: Zac Medico <zmedico@gentoo.org>
1 file changed