We had a lot of flaky test failures from TestAuth. The error message (WHICH IS NOT VISIBLE IN JEKNINS, only in tests.json):
```
FAIL: TestAuth_Register_NameSpecialChars/Postgres (1.04s)
panic: runtime error: index out of range [0] with length 0 [recovered]
panic: runtime error: index out of range [0] with length 0
goroutine 3473 [running]:
testing.tRunner.func1.2({0x235fe40, 0xc000fe6a08})
/usr/local/go/src/testing/testing.go:1209 +0x36c
testing.tRunner.func1()
/usr/local/go/src/testing/testing.go:1212 +0x3b6
panic({0x235fe40, 0xc000fe6a08})
/usr/local/go/src/runtime/panic.go:1047 +0x266
storj.io/storj/satellite/console/consoleweb/consoleapi_test.TestAuth_Register_NameSpecialChars.func1(0xc001a281a0, 0x289d650, 0xc001a30000)
/var/lib/jenkins/workspace/storj-gerrit-verify/satellite/console/consoleweb/consoleapi/auth_test.go:773 +0x785
storj.io/storj/private/testplanet.Run.func1.1({0x289c770, 0xc0001b8008})
/var/lib/jenkins/workspace/storj-gerrit-verify/private/testplanet/run.go:67 +0x732
storj.io/storj/private/testmonkit.RunWith({0x289c770, 0xc0001b8008}, {0x28d89b0, 0xc001a281a0}, {0x1, {0x0, 0x0}, {0x0, 0x0, 0x0}}, ...)
```
The root cause:
testplanet uses a simulated mail sender which clicks to all the registration links by default (async).
These tests creat links and check the unverified users, but without enough luck the mail sender may already clicks to the link which makes the user verified.
Change-Id: I17cd6bf4ae3e7adc223ec693976bb609370f0c44
