fix missing dots

[Jnchk]

Package Testing of go 1.11 is more strict about arguments checking to print-like functions. We will get the error bellow if we left args without dots.

go test -v
# github.com/muesli/cache2go
./cachetable.go:330: missing ... in args forwarded to print-like function
FAIL    github.com/muesli/cache2go [build failed]

OS version:
manjaro 18.0.0-rc
go 1.11.1

[coveralls]

Coverage remained the same at 100.0% when pulling 1a478e9 on Jnchk:fix-missing-dots into 5a18398 on muesli:master.

[coveralls]

Coverage remained the same at 100.0% when pulling 1a478e9 on Jnchk:fix-missing-dots into 5a18398 on muesli:master.

[muesli]

Thank you for your contribution!