virsh.sysinfo: Don't fail over a single space

Found an instance on a test machine where the processor string was
prefixed with a space from libvirt, which caused a failure since the
dmidecode output comparison had spaces stripped. Perform the same strip
on the libvirt returned data to avoid this.
Merge pull request #78 from jferlan/sysinfo

virsh.sysinfo: Don't fail over a single space