bug#30142: pipe of 'guix --version' produces error

[George myglc2 Clemmer]

EXAMPLE:
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address@hidden ~/www/VM-on-GuixSD$ guix --version | head -n 1
guix (GNU Guix) 0.14.0.617-e2f37
Backtrace:
           5 (primitive-load 
"/gnu/store/nxdxbad50ydp1nhmgzvlwbk0jkkdc28r-guix-0.14.0-3.f76ff98/bin/.guix-real")
In guix/ui.scm:
    390:2  4 (show-version-and-exit _)
In ice-9/format.scm:
  1590:19  3 (format #t "Copyright ~a 2017 ~a" "(C)" "the Guix authors\n")
   261:19  2 (format:format-work "Copyright ~a 2017 ~a" ("(C)" "the Guix 
authors\n"))
    70:10  1 (format:out-obj-padded _ _ _ _)
In unknown file:
           0 (display "the Guix authors\n" #<output: file 1>)

ERROR: In procedure display:
ERROR: In procedure fport_write: Broken pipe
address@hidden ~/www/VM-on-GuixSD$ guix --version | head -n 1
guix (GNU Guix) 0.14.0.617-e2f37
Backtrace:
           5 (primitive-load 
"/gnu/store/nxdxbad50ydp1nhmgzvlwbk0jkkdc28r-guix-0.14.0-3.f76ff98/bin/.guix-real")
In guix/ui.scm:
    390:2  4 (show-version-and-exit _)
In ice-9/format.scm:
  1590:19  3 (format #t "Copyright ~a 2017 ~a" "(C)" "the Guix authors\n")
   261:19  2 (format:format-work "Copyright ~a 2017 ~a" ("(C)" "the Guix 
authors\n"))
    70:10  1 (format:out-obj-padded _ _ _ _)
In unknown file:
           0 (display "the Guix authors\n" #<output: file 1>)

ERROR: In procedure display:
ERROR: In procedure fport_write: Broken pipe
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VERSION:
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address@hidden ~$ guix --version
guix (GNU Guix) 0.14.0.617-e2f37
Copyright (C) 2017 the Guix authors
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.