portageq pquery: Search ebuilds in all repositories be default.

--all-repos option is no longer supported.
1 call to deprecated portage.repository.config.RepoConfigLoader.mainRepo() function
has been deleted.
portage.dbapi.bintree.binarytree: Delete main-repository-reliant microoptimization in index of binary packages.

This microoptimization cannot work when no main repository exists.
1 call to deprecated portage.repository.config.RepoConfigLoader.mainRepo() function
has been deleted.
portage.tests.dbapi.test_portdb_cache: Delete deprecated code.

9 calls to deprecated portage.repository.config.RepoConfigLoader.mainRepoLocation()
function have been deleted.
portage.tests.glsa.test_security_set: Delete deprecated code.

1 call to deprecated portage.repository.config.RepoConfigLoader.mainRepoLocation()
function has been deleted.
emerge --info: Check metadata/timestamp.chk in all repositories.

1 use of deprecated PORTDIR has been deleted.