fixes defaut database configuration for tests

tracim/test.ini

 port = 8080
 
 [app:main]
-sqlalchemy.url = mysql+oursql://tracim:tracim@localhost/tracim_test
+sqlalchemy.url = postgresql://postgres:dummy@127.0.0.1:5432/tracim_test?client_encoding=utf8
 use = config:development.ini
 
 [app:main_without_authn]
 skip_authentication = True
 
 [app:ldap]
-sqlalchemy.url = mysql+oursql://tracim:tracim@localhost/tracim_test
+sqlalchemy.url = postgresql://postgres:dummy@127.0.0.1:5432/tracim_test?client_encoding=utf8
 auth_type = ldap
 ldap_url = ldap://localhost:3333
 ldap_base_dn = dc=directory,dc=fsf,dc=org
 use = config:development.ini
 
 [app:radicale]
-sqlalchemy.url = mysql+oursql://tracim:tracim@localhost/tracim_test
+sqlalchemy.url = postgresql://postgres:dummy@127.0.0.1:5432/tracim_test?client_encoding=utf8
+
 use = config:development.ini
 
 # Add additional test specific configuration options as necessary.