Make sure grit restores old timeout value even if exception occured

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

lib/grit/git.rb

@@ -90,9 +90,13 @@ module Grit
     def self.with_timeout(timeout = 10)
       old_timeout = Grit::Git.git_timeout
-      Grit::Git.git_timeout = timeout
-      yield
-      Grit::Git.git_timeout = old_timeout
+
+      begin
+        Grit::Git.git_timeout = timeout
+        yield
+      ensure
+        Grit::Git.git_timeout = old_timeout
+      end
     end
     attr_accessor :git_dir, :bytes_read, :work_tree

test/test_git.rb

@@ -43,6 +43,18 @@ class TestGit < Test::Unit::TestCase
     @git.something
   end
+  def test_with_timeout_restored
+    begin
+      Grit::Git.with_timeout(4) do
+        raise 'wow'
+      end
+    rescue
+      nil
+    end
+
+    assert_equal Grit::Git.git_timeout, 5
+  end
+
   def test_can_skip_timeout
     Timeout.expects(:timeout).never
     @git.something(:timeout => false)