test: improve test for urlencoded user:pass
test: improve test for urlencoded user:pass

Signed-off-by: Santiago M. Mola <8da22c45572ff7532871766932ae66e63da3e927@mola.io>

src-d/go-git,go-git/go-git,mcuadros/go-git,mcuadros/go-git,src-d/go-git,go-git/go-git