fix second calling fetch method at same cursor object always return []

set hasMoreRows=True at cursor#execute

If you call execute/fetch method twice at same cursor object, second fetch always return [] because hasMoreRows is True.

This is not good.

for example,
cur.execute("select * from hoge")
print cur.fetch()
cur.execute("select * from piyo")
print cur.fetch() # always []
Merge pull request #21 from wyukawa/feature-hasMoreRows

fix second calling fetch method at same cursor object always return []