update on smpirun script to accept -trace argument with the name of the tracefile

update on smpirun script to accept -trace argument with the name of the tracefile

details:
- among other parameters, smpirun accepts:
smpirun (...) -trace tracefile.trace (...) ./bcast (...)
- the parameter is translated to the following options to the simulator
--cfg=tracing/filename:${TRACEOPT} --cfg=tracing/smpi:1 where TRACEOPT
is the trace file passed as parameter

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/simgrid/simgrid/trunk@8147 48e7efb5-ca39-0410-a469-dd3cf9ba447f