Redundant whitespace in the emitted script when using the local launcher

[vkarak]

That's simply a cosmetic thing, but it'd be nice to fix it. If the local launcher is used a preceding space is emitted in the launcher line:

#!/bin/bash
. $SPACK_ROOT/share/spack/setup-env.sh
spack env activate -V -d myenv
 bzip2 --help