Make the help module read documentation directory from config

data/etc/plinth/plinth.config

@@ -8,8 +8,9 @@ file_root = /usr/share/plinth/static
 data_dir = /var/lib/plinth
 log_dir = /var/log/plinth
 pid_dir = /var/run
-actions_dir = /usr/share/plinth/actions
 server_dir = plinth/
+actions_dir = /usr/share/plinth/actions
+doc_dir = /usr/share/doc/plinth
 
 # file locations
 store_file = %(data_dir)s/store.sqlite3

plinth/cfg.py

@@ -13,6 +13,7 @@ data_dir = None
 store_file = None
 user_db = None
 actions_dir = None
+doc_dir = None
 status_log_file = None
 access_log_file = None
 pidfile = None
@@ -44,6 +45,7 @@ def read():
                     ('Path', 'store_file'),
                     ('Path', 'user_db'),
                     ('Path', 'actions_dir'),
+                    ('Path', 'doc_dir'),
                     ('Path', 'status_log_file'),
                     ('Path', 'access_log_file'),
                     ('Path', 'pidfile'),

plinth/modules/help/help.py

@@ -36,7 +36,7 @@ def about(request):
 def helppage(request, page):
     """Serve a help page from the 'doc' directory"""
     try:
-        with open(os.path.join('doc', '%s.part.html' % page), 'r') \
+        with open(os.path.join(cfg.doc_dir, '%s.part.html' % page), 'r') \
                 as input_file:
             main = input_file.read()
     except IOError: