Return a fake MakeDB function when documenting plugins.

There's no need to actually search for valid database backends when
documenting.  It only gets in the way of the actual document generation
process.

Signed-off-by: James Vega <jamessan@users.sourceforge.net>

plugins/__init__.py

@@ -105,6 +105,12 @@ class NoSuitableDatabase(Exception):
                       self.suitable)
 
 def DB(filename, types):
+    # We don't care if any of the DBs are actually available when
+    # documenting, so just fake that we found something suitable
+    if world.documenting:
+        def junk(*args, **kwargs):
+            pass
+        return junk
     filename = conf.supybot.directories.data.dirize(filename)
     def MakeDB(*args, **kwargs):
         for type in conf.supybot.databases():