Fixing a few JSHint warnings in the /tests

Fixing some JSHint warnings in the /test/** directory
```
$ grunt jshint
Running "jshint:files" (jshint) task
>> 68 files lint free.

Done, without errors.
```

And all the tests still pass locally:
```
> tap ./test/run

ok test/run/account_reset_token_tests.js .............. 13/13
ok test/run/api_error_tests.js .......................... 7/7
ok test/run/auth_token_tests.js ....................... 16/16
ok test/run/browserid_protocol_tests.js ................. 6/6
ok test/run/db_tests.js ............................... 59/59
ok test/run/forgot_password_token_tests.js ............ 17/17
ok test/run/hkdf_tests.js ............................... 5/5
ok test/run/integration_tests.js ...................... 36/36
ok test/run/key_fetch_token_tests.js .................. 16/16
ok test/run/key_stretch_tests.js ...................... 14/14
ok test/run/pbkdf2_tests.js ............................. 4/4
ok test/run/raw_password_tests.js ..................... 14/14
ok test/run/scrypt_tests.js ............................. 3/3
ok test/run/session_token_tests.js .................... 12/12
ok test/run/signer_tests.js ......................... 124/124
ok test/run/srp_session_tests.js ........................ 5/5
ok test/run/verification_tests.js ..................... 29/29
total ............................................... 380/380

ok
```