calc_rdf_gromacs.sh: fixed a bug in awk code to calc begin time
calc_rdf_gromacs.sh: fixed a bug in awk code to calc begin time

vaidyanathanms/votca.csg,vaidyanathanms/votca.csg,Pallavi-Banerjee21/votca.csg,Pallavi-Banerjee21/votca.csg,vaidyanathanms/votca.csg,vaidyanathanms/votca.csg,vaidyanathanms/votca.csg,Pallavi-Banerjee21/votca.csg,Pallavi-Banerjee21/votca.csg,Pallavi-Banerjee21/votca.csg,Pallavi-Banerjee21/votca.csg