nodepool: pause gentoo and tumbleweed builds
Both of these are failing in ways that look like we need to fix them
in dib.  Stop attempting to build them for now.
@@ -277,7 +277,7 @@ diskimages:
- name: gentoo-17-0-systemd
parent: base
- pause: false
+ pause: true
elements:
- gentoo
env-vars:
@@ -303,7 +303,7 @@ diskimages:
- name: opensuse-tumbleweed
parent: base
- pause: false
+ pause: true
elements:
- opensuse-minimal
- cache-devstack
