Added an optional --force parameter for gitlab-projects fetch-remote

The optional parameter will decide wheter to fetch using --force or not.
fetching with --force is a requirement for Gitlab Geo secondary node
replication.

VERSION

-2.6.10
+2.6.11

lib/gitlab_projects.rb

@@ -135,8 +135,13 @@ class GitlabProjects
 
     # timeout for fetch
     timeout = (ARGV.shift || 120).to_i
+
+    # fetch with --force ?
+    forced = (ARGV.shift == '--force' || false)
+
     $logger.info "Fetching remote #{@name} for project #{@project_name}."
     cmd = %W(git --git-dir=#{full_path} fetch #{@name} --tags)
+    cmd << '--force' if forced
     pid = Process.spawn(*cmd)
 
     begin