gitlab-ci: Add USER environment variable to buildman/patman tests

The way that some of the tests here are designed, they expect USER to be
set in the environment.  This is not the case in the docker images, so
set a reasonable value.
Signed-off-by: NTom Rini <trini@konsulko.com>

.gitlab-ci.yml

@@ -152,12 +152,14 @@ Run patman testsuite:
   script:
     - git config --global user.name "GitLab CI Runner"
     - git config --global user.email trini@konsulko.com
+    - export USER=gitlab
     - ./tools/patman/patman --test
 
 Run buildman testsuite:
   tags: [ 'all' ]
   stage: testsuites
   script:
+    - export USER=gitlab
     - ./tools/buildman/buildman -t
 
 Run binman and dtoc testsuite: