vsh: Fix the incorrect environment variable prefix in error message
vsh: Fix the incorrect environment variable prefix in error message

Unlike the other error messages in vshInitDebug, this one relied on a hardcoded
name of a variable instead of using the prefix of the tool calling the init
routine.

Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1393854

Signed-off-by: Erik Skultety <2c14d38fa47c8799f1b9c16280abe27f8edfec6e@redhat.com>

nertpinx/libvirt,andreabolognani/libvirt,libvirt/libvirt,jardasgit/libvirt,datto/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,olafhering/libvirt,taget/libvirt,jfehlig/libvirt,jardasgit/libvirt,taget/libvirt,andreabolognani/libvirt,fabianfreyer/libvirt,datto/libvirt,VenkatDatta/libvirt,jfehlig/libvirt,jardasgit/libvirt,libvirt/libvirt,libvirt/libvirt,libvirt/libvirt,jfehlig/libvirt,nertpinx/libvirt,crobinso/libvirt,olafhering/libvirt,eskultety/libvirt,jardasgit/libvirt,olafhering/libvirt,zippy2/libvirt,zippy2/libvirt,eskultety/libvirt,VenkatDatta/libvirt,fabianfreyer/libvirt,fabianfreyer/libvirt,olafhering/libvirt,zippy2/libvirt,eskultety/libvirt,zippy2/libvirt,taget/libvirt,taget/libvirt,fabianfreyer/libvirt,crobinso/libvirt,taget/libvirt,eskultety/libvirt,datto/libvirt,crobinso/libvirt,datto/libvirt,andreabolognani/libvirt,nertpinx/libvirt,jardasgit/libvirt,crobinso/libvirt,andreabolognani/libvirt,VenkatDatta/libvirt,VenkatDatta/libvirt,eskultety/libvirt,VenkatDatta/libvirt,datto/libvirt,jfehlig/libvirt,andreabolognani/libvirt,nertpinx/libvirt