maps: handle sqlite lock error triggered by PRAGMA statements "self._db.execute('PRAGMA cache_size=%d' % (-cachesize))" could raise "OperationalError: database is locked". Therefore move PRAGMA statements inside "self._transaction" which handles the "locked" error automatically.

import test_util

import unittest

class TestFetchBinaryFiles(test_util.TestBase):
    stupid_mode_tests = True

    def test_binaryfiles(self):
        repo = self._load_fixture_and_fetch('binaryfiles.svndump')
        self.assertEqual('cce7fe400d8d', str(repo['tip']))