Try to fix errors on Travis

I'm seeing "ProgrammingError: no schema has been selected to create in."
Maybe we can drop and recreate the public schema?

Author: chadwhitacre

postgres/__init__.py

@@ -874,6 +874,8 @@ def make(self, values):
 
 if __name__ == '__main__':
     db = Postgres("postgres://jrandom@localhost/test")
+    db.run("DROP SCHEMA IF EXISTS public CASCADE")
+    db.run("CREATE SCHEMA public")
     db.run("DROP TABLE IF EXISTS foo CASCADE")
     import doctest
     doctest.testmod()

postgres/orm.py

@@ -261,6 +261,8 @@ def update_attributes(self, **kw):
 
     from postgres import Postgres
     db = Postgres("postgres://jrandom@localhost/test")
+    db.run("DROP SCHEMA IF EXISTS public CASCADE")
+    db.run("CREATE SCHEMA public")
     db.run("DROP TABLE IF EXISTS foo CASCADE")
     db.run("CREATE TABLE foo (bar text, baz int)")
     db.run("INSERT INTO foo VALUES ('blam', 42)")