Build in steps to ensure DISTCC_DIR is set up correctly

When the first distcc job to run happens in the ebuild setup phase, the
permissions in DISTCC_DIR are not set up correctly--they are owned by
root instead of portage.  Just building a small package before chromium,
like its dependency, snappy, cause the DISTCC_DIR to set up correctly.

.gitlab-ci.yml

@@ -5,9 +5,13 @@
   tags: ['nest']
   script:
     - 'emerge --sync'
-    - 'MAKEOPTS="$CI_HOST_MAKEOPTS"
-       PORTAGE_TMPDIR=/cache
-       emerge -v -j1 --buildpkg www-client/chromium'
+    - 'emerge -v1 -j1 -k n app-arch/snappy' # Ensure DISTCC_DIR is set up correctly
+    - 'emerge -v1 -j --onlydeps www-client/chromium'
+    - 'emerge -v -j1 --buildpkgonly www-client/chromium'
+  variables:
+    EMERGE_DEFAULT_OPTS: '$CI_HOST_EMERGE_DEFAULT_OPTS'
+    MAKEOPTS: '$CI_HOST_MAKEOPTS'
+    PORTAGE_TMPDIR: '/cache'
 
 'Build haswell':
   <<: *template