Fix GitWeb Caching

GitWeb Caching won't work when its cgi file is executed from outside.
Same approach will also work with vanilla GitWeb.

Change-Id: I9ee93337f492eceb520273d71295a0d16631f718
Signed-off-by: Dariusz Luksza <dariusz@luksza.org>

gerrit-httpd/src/main/java/com/google/gerrit/httpd/gitweb/GitWebServlet.java

@@ -416,7 +416,8 @@ class GitWebServlet extends HttpServlet {
       final Repository repo) throws IOException {
     final Process proc =
         Runtime.getRuntime().exec(new String[] {gitwebCgi.getAbsolutePath()},
-            makeEnv(req, project), repo.getDirectory());
+            makeEnv(req, project),
+            gitwebCgi.getAbsoluteFile().getParentFile());
 
     copyStderrToLog(proc.getErrorStream());
     if (0 < req.getContentLength()) {