hob was adding the redundant characters "\1" in SSTATE_MIRRORS variable. If
needed it is expected the user will add this instead so remove the code
that was doing this.
[YOCTO #6600]
(Bitbake rev: 73bf120062fc00c7e26dc4e77a7d140658d89daf)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>