[FIX] drop database fails when done before connecting to server.

lp bug: https://launchpad.net/bugs/924783 fixed

bzr revid: ronald@therp.nl-20120201113759-wi2kogl2x1lsxk7g

.bzrignore

@@ -21,3 +21,5 @@ bin/pil*.py
 .project
 .pydevproject
 .settings
+profiledata
+*.moved

openerp/sql_db.py

@@ -509,8 +509,10 @@ def db_connect(db_name):
     return Connection(_Pool, db_name)
 
 def close_db(db_name):
+    global _Pool
     """ You might want to call openerp.modules.registry.RegistryManager.delete(db_name) along this function."""
-    _Pool.close_all(dsn(db_name))
+    if _Pool:
+        _Pool.close_all(dsn(db_name))
     ct = currentThread()
     if hasattr(ct, 'dbname'):
         delattr(ct, 'dbname')