[opensuse] Do not clear repositories when creating image
Creating disk image fro openSUSE with PUBLISH_HDD_1 will going through installation procedure. With HAVE_ADDON_REPOS, it will add default online repositories. But after installation it always call update/zypper_clear_repos to clear all online repos, no matter if KEEP_ONLINE_REPOS was set.
zypper_clear_repos was called if need_clear_repos() return true.
So add "&& !get_var('KEEP_ONLINE_REPOS')" in return code for need_clear_repos() should work.
Update(20190718): By investigation of lib/main_common.pm and existing tests create_hdd_gnome in o.o.o., it is found that KEEP_ONLINE_REPOS does work, but with an indirect way. When KEEP_ONLINE_REPOS is set,
is_repo_replacement_required() return false. Meanwhile, if
have_addn_repos()(should set SUSEMIRROR) was true, then
console/zypper_ar will be triggered. Therefore, the cleared repos will be added back to the system before installation finished.