gitweb: Silence 'Variable VAR may be unavailable' warnings

When $projects_list points to a directory, and git_get_projects_list
scans this directory for repositories, there can be generated the
following warnings (for persistent services like mod_perl or plackup):

  Variable "$project_maxdepth" may be unavailable at gitweb.cgi line 2443.
  Variable "$projectroot" may be unavailable at gitweb.cgi line 2451.

Those are false positives; silence those warnings by explicitely
declaring $project_maxdepth and $projectroot with 'our', as global
variables, in anonymous subrotine passed to File::Find::find.
Signed-off-by: NJakub Narebski <jnareb@gmail.com>
Signed-off-by: NJunio C Hamano <gitster@pobox.com>

gitweb/gitweb.perl

@@ -1520,6 +1520,9 @@ sub git_get_projects_list {
 			follow_skip => 2, # ignore duplicates
 			dangling_symlinks => 0, # ignore dangling symlinks, silently
 			wanted => sub {
+				# global variables
+				our $project_maxdepth;
+				our $projectroot;
 				# skip project-list toplevel, if we get it.
 				return if (m!^[/.]$!);
 				# only directories can be git repositories