Increase project import timeout from 4 minutes to 15 minutes

Many users were experiencing timeouts when we only allowed
4 minutes before a timeout. A 15 minute timeout is more
than reasonable and prevents us from having to add a
configuration for this.

Fixes gitlab-org/gitlab-ee#246

CHANGELOG

@@ -14,6 +14,7 @@ v 8.5.0 (unreleased)
   - Fix diff comments loaded by AJAX to load comment with diff in discussion tab
   - Whitelist raw "abbr" elements when parsing Markdown (Benedict Etzel)
   - Don't vendor minified JS
+  - Increase project import timeout to 15 minutes
   - Display 404 error on group not found
   - Track project import failure
   - Support Two-factor Authentication for LDAP users

app/views/shared/_import_form.html.haml

@@ -11,6 +11,6 @@
         %li
           If your HTTP repository is not publicly accessible, add authentication information to the URL: <code>https://username:password@gitlab.company.com/group/project.git</code>.
         %li
-          The import will time out after 4 minutes. For big repositories, use a clone/push combination.
+          The import will time out after 15 minutes. For repositories that take longer, use a clone/push combination.
         %li
           To migrate an SVN repository, check out #{link_to "this document", "http://doc.gitlab.com/ce/workflow/importing/migrating_from_svn.html"}.

lib/gitlab/backend/shell.rb

@@ -36,7 +36,7 @@ module Gitlab
     #   import_repository("gitlab/gitlab-ci", "https://github.com/randx/six.git")
     #
     def import_repository(name, url)
-      output, status = Popen::popen([gitlab_shell_projects_path, 'import-project', "#{name}.git", url, '240'])
+      output, status = Popen::popen([gitlab_shell_projects_path, 'import-project', "#{name}.git", url, '900'])
       raise Error, output unless status.zero?
       true
     end