package/sslh: fix script, does not build in parallel

package/sslh: fix script, does not build in parallel

The Makefile is not parallel-safe, so we build with MAKE1. Since the
source is very small, this has minor impact on performance.

The genver.sh script contains a troll character U+c2a0 (non-break space)
which is refused by some versions of /bin/sh. Patch it away.

Fixes:
    http://autobuild.buildroot.net/results/867/867c74ed74fd04ab06d1a10ff34ca177fe005fd2/
    http://autobuild.buildroot.net/results/f97/f971629bc99147f9014e52c6ef71c3417faa6b67/

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: David Bachelart <david.bachelart@bbright.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>