#703 - Fixes race condition when using express-session with custom store

[pragmaticivan]

fixes #703

Checklist

• I have read the CONTRIBUTING guidelines.
• I have added test cases which verify the correct operation of this feature or patch.
• I have added documentation pertaining to this feature or patch.
• The automated test suite ($ make test) executes successfully.
• The automated code linting ($ make lint) executes successfully.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 6bd689c on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[coveralls]

Coverage decreased (-1.1%) to 97.772% when pulling 416abce on pragmaticivan:bugfix/703-race-condition-session-with-store into 882d65e on jaredhanson:master.

[zypA13510]

Related or duplicate: #504, #680.