use system_timer gem if installed to prevent 'git fetch origin' from …

…hanging. See https://cruisecontrolrb.lighthouseapp.com/projects/9150-cruise-control-rb/tickets/229-sometimes-git-hangs

config/initializers/system_timer.rb

@@ -0,0 +1,10 @@
+# If installed, use SystemTimer to avoid git.rb causing builder to hang due to intermittent network issues.  See:
+# https://cruisecontrolrb.lighthouseapp.com/projects/9150-cruise-control-rb/tickets/229-sometimes-git-hangs
+# http://ph7spot.com/musings/system-timer
+begin
+  require 'system_timer'
+  MyTimer = SystemTimer
+rescue LoadError
+  require 'timeout'
+  MyTimer = Timeout
+end

lib/source_control/git.rb

@@ -94,7 +94,9 @@ def filter_revisions_by_subdirectory(revisions, subdir)
     end
 
     def load_new_changesets_from_origin
-      Timeout.timeout(Configuration.git_load_new_changesets_timeout, Timeout::Error) do
+      # NOTE: Git network problems may cause CruiseControl.rb to hang unless you install the system_timer gem.
+      # See: https://cruisecontrolrb.lighthouseapp.com/projects/9150-cruise-control-rb/tickets/229-sometimes-git-hangs
+      MyTimer.timeout(Configuration.git_load_new_changesets_timeout) do
         git("fetch", ["origin"])
       end
     rescue Timeout::Error => e