nil pointer dereference in url.

[cjslep]

Noticed the site was down due to this SIGSEGV:

panic: runtime error: invalid memory address or nil pointer dereference

goroutine 13679 [running]:
net/url.(*URL).String
        /usr/local/go/src/net/url/url.go:775
github.com/go-fed/testsuite/server.(*Recorder).Add
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/recorder.go:54
github.com/go-fed/testsuite/server.(*baseTest).helperMustAddToDatabase
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/tests.go:269
github.com/go-fed/testsuite/server.newCommonTests.func1
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/tests.go:920
github.com/go-fed/testsuite/server.(*baseTest).MaybeRunResult
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/tests.go:256
github.com/go-fed/testsuite/server.(*TestRunner).iterate
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/testrunner.go:106
github.com/go-fed/testsuite/server.(*TestRunner).Run.func1
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/testrunner.go:71
created by github.com/go-fed/testsuite/server.(*TestRunner).Run
        /Users/cjslep/go/src/github.com/go-fed/testsuite/server/testrunner.go:65