[FIX] odoo.py windows compatibility

Prevent infinite loop when installing on windows
Fixes #2825

Tested to work on
* Git Bash v1.9.4 on Windows 8.1 Professional
* Ubuntu 12.04.5 LTS

odoo.py

@@ -47,14 +47,14 @@ def git_locate():
         os.chdir('odoo')
 
     path = os.getcwd()
-    while path != '/':
+    while path != os.path.abspath(os.sep):
         gitconfig_path = os.path.join(path, '.git/config')
         if os.path.isfile(gitconfig_path):
             release_py = os.path.join(path, 'openerp/release.py')
             if os.path.isfile(release_py):
                 break
         path = os.path.dirname(path)
-    if path == '/':
+    if path == os.path.abspath(os.sep):
         path = None
     return path