Get the PROXY1 length check right, it is only the length until the first \n which is limited.
Get the PROXY1 length check right, it is only the length until
the first \n which is limited.

Fixes #1728

feld/Varnish-Cache,mrhmouse/Varnish-Cache,zhoualbeart/Varnish-Cache,franciscovg/Varnish-Cache,chrismoulton/Varnish-Cache,varnish/Varnish-Cache,mrhmouse/Varnish-Cache,zhoualbeart/Varnish-Cache,ajasty-cavium/Varnish-Cache,gquintard/Varnish-Cache,chrismoulton/Varnish-Cache,mrhmouse/Varnish-Cache,gquintard/Varnish-Cache,varnish/Varnish-Cache,chrismoulton/Varnish-Cache,franciscovg/Varnish-Cache,franciscovg/Varnish-Cache,zhoualbeart/Varnish-Cache,mrhmouse/Varnish-Cache,feld/Varnish-Cache,gquintard/Varnish-Cache,gauthier-delacroix/Varnish-Cache,varnish/Varnish-Cache,gquintard/Varnish-Cache,zhoualbeart/Varnish-Cache,gauthier-delacroix/Varnish-Cache,zhoualbeart/Varnish-Cache,ajasty-cavium/Varnish-Cache,mrhmouse/Varnish-Cache,gauthier-delacroix/Varnish-Cache,chrismoulton/Varnish-Cache,feld/Varnish-Cache,chrismoulton/Varnish-Cache,feld/Varnish-Cache,gauthier-delacroix/Varnish-Cache,franciscovg/Varnish-Cache,ajasty-cavium/Varnish-Cache,varnish/Varnish-Cache,ajasty-cavium/Varnish-Cache,varnish/Varnish-Cache,gauthier-delacroix/Varnish-Cache,franciscovg/Varnish-Cache,feld/Varnish-Cache,ajasty-cavium/Varnish-Cache