PAT panics if there are any unexpected files in output/csvs/

[anEXPer]

./pat -config=local-config.yml
panic: runtime error: index out of range

goroutine 1 [running]:
runtime.panic(0x2ef800, 0x6d97b7)
    /usr/local/Cellar/go/1.2.2/libexec/src/pkg/runtime/panic.c:266 +0xb6
github.com/cloudfoundry-incubator/pat/store.(*CsvStore).LoadAll(0xc21000aba0, 0xc210058580, 0x5, 0x8, 0x0, ...)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/store/csv.go:190 +0x3d3
github.com/cloudfoundry-incubator/pat/laboratory.(*lab).reload(0xc21006b120)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/laboratory/laboratory.go:37 +0x2f
github.com/cloudfoundry-incubator/pat/laboratory.NewLaboratory(0x8137d8, 0xc21000aba0, 0x1, 0x1)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/laboratory/laboratory.go:32 +0x8e
github.com/cloudfoundry-incubator/pat/cmdline.func·002(0x8137d8, 0xc21000aba0, 0x0, 0x0)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:131 +0x43
github.com/cloudfoundry-incubator/pat/cmdline.func·006(0x8137d8, 0xc21000aba0, 0x8137d8, 0xc21000aba0)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:66 +0xcc
github.com/cloudfoundry-incubator/pat/store.WithStore(0xc21000ab60, 0xc21000ab60, 0x98ba0)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/store/config.go:32 +0xd6
github.com/cloudfoundry-incubator/pat/cmdline.func·007(0xc210000398, 0xc210044a50)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:82 +0x60
github.com/cloudfoundry-incubator/pat/cmdline.validateParameters(0x813748, 0xc210000398, 0x853dc0, 0x8137b0, 0xc210000398)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:123 +0x268
github.com/cloudfoundry-incubator/pat/cmdline.func·008(0x813748, 0xc210000398, 0x813748, 0xc210000398)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:83 +0x8d
github.com/cloudfoundry-incubator/pat/benchmarker.WithConfiguredWorkerAndSlaves(0xc210044e10, 0x2e7a20, 0x0)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/benchmarker/config.go:28 +0xec
github.com/cloudfoundry-incubator/pat/cmdline.func·001(0xc210044e10, 0xc210044e10, 0x34b300)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:127 +0x27
github.com/cloudfoundry-incubator/pat/cmdline.RunCommandLine(0xc21001eea0, 0xc21000a010)
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/cmdline/cmdline.go:84 +0x19e
main.main()
    /Users/pivotal/go/src/github.com/cloudfoundry-incubator/pat/main.go:31 +0x267

To reproduce:

1. From the pat dir, touch output/csvs/test.csv
2. Try to run PAT.