bug#12827: [2.0.6] web client: fails to parse 404 header

[Ludovic Courtès]

scheme@(guile-user)> (use-modules (web client) (web uri))
scheme@(guile-user)> (http-get (string->uri 
"http://www.gnu.org/does-not-exist";))
web/http.scm:191:11: In procedure read-header:
web/http.scm:191:11: Bad uri header component: gnu-404.html

Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
scheme@(guile-user) [1]> ,bt
In web/client.scm:
    127:4  3 (http-get #<<uri> scheme: http userinfo: #f host: "www.gnu.org" 
port: #f path: "/does-not-exist" query: #f fragment: #f> #:port #<input-output: 
socket 9> #:version (1 . 1) #:keep-alive? #f #:extra-headers () # #)
In web/response.scm:
    188:6  2 (read-response #<input-output: socket 9>)
In web/http.scm:
   225:33  1 (lp ((server . "Apache/2.2.14") (date . #<date nanosecond: 0 
second: 12 minute: 36 hour: 20 day: 7 month: 11 year: 2012 zone-offset: 0>)))
   191:11  0 (read-header #<input-output: socket 9>)
scheme@(guile-user) [1]> ,locals
  Local variables:
  $5 = port = #<input-output: socket 9>
  $6 = line = "Content-Location: gnu-404.html"
  $7 = delim = 16
  $8 = sym = content-location

Ludo’.