scm: set supporting directory revisions or not at scm level.

git-svn-id: svn+ssh://rubyforge.org/var/svn/redmine/trunk@5144 e93f8b46-1217-0410-a6f0-8f06a7374b81

app/models/repository.rb

@@ -75,6 +75,10 @@ class Repository < ActiveRecord::Base
     true
   end
   
+  def supports_directory_revisions?
+    false
+  end
+  
   def entry(path=nil, identifier=nil)
     scm.entry(path, identifier)
   end

app/models/repository/git.rb

@@ -36,6 +36,10 @@ class Repository::Git < Repository
     'Git'
   end
 
+  def supports_directory_revisions?
+    true
+  end
+
   def repo_log_encoding
     'UTF-8'
   end

app/models/repository/mercurial.rb

@@ -41,6 +41,10 @@ class Repository::Mercurial < Repository
     'Mercurial'
   end
 
+  def supports_directory_revisions?
+    true
+  end
+
   def repo_log_encoding
     'UTF-8'
   end

app/models/repository/subversion.rb

@@ -30,6 +30,10 @@ class Repository::Subversion < Repository
     'Subversion'
   end
 
+  def supports_directory_revisions?
+    true
+  end
+
   def repo_log_encoding
     'UTF-8'
   end