a bug in thisroot.sh (ROOT env setup) for bash

The script bin/thisroot.sh would not be able to set up ROOT env under bash if CDPATH is defined. The following lines in bin/thisroot.sh

    thisroot=$(dirname ${BASH_ARGV[0]})

    ROOTSYS=$(cd ${thisroot}/..;pwd); export ROOTSYS

will result in an incorrect ROOTSYS if $thisroot is a relative path. In fact, the value of ROOTSYS will be 2 sames path delimited by a space, something like:

/afs/cern.ch/sw/lcg/app/releases/ROOT/6.04.02/x86_64-slc6-gcc48-opt/root /afs/cern.ch/sw/lcg/app/releases/ROOT/6.04.02/x86_64-slc6-gcc48-opt/root

Redirecting the output of cd command to /dev/null could resolve this problem.

Please help fix this problem.

--Shuwei