[IMP] cli: allows to run odoo with openshift

For containers using random uids[1], use the higher level method getpass.getuser
which as the same effect but also looks consider the environment variables to
determine the user name.

Details from
http://blog.dscpl.com.au/2015/12/unknown-user-when-running-docker.html

CLA signature for akram

Closes #26452

[1] openshift or docker as explained at
http://blog.dscpl.com.au/2015/12/random-user-ids-when-running-docker.html

odoo/cli/server.py

@@ -36,8 +36,8 @@ _logger = logging.getLogger('odoo')
 def check_root_user():
     """Warn if the process's user is 'root' (on POSIX system)."""
     if os.name == 'posix':
-        import pwd
-        if pwd.getpwuid(os.getuid())[0] == 'root':
+        import getpass
+        if getpass.getuser() == 'root':
             sys.stderr.write("Running as user 'root' is a security risk.\n")
 
 def check_postgres_user():