Repair tox-run for case of no tox logs to archive

Revise tox-run.sh to guard against glob matching no tox log files.
In that case the pattern is passed to the cp command, which fails.
Detect the cp failure ('cp: cannot stat ..') and exit the loop.
I introduced this new and undesired behavior by adding -e in
change 76a0761, so the script stops when the cp command fails.

Change-Id: I1d60bb69e270c4aea413f4f14cf2d4f8f672853b
Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>