Fix #616: space in group crashes configure script
Fix #616: space in group crashes configure script

Fix a bug in the configure script where it would crash if there was a
space in the linux group name while checking for the record length. Now
the stat command is used instead of ls.

nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,mchamberland/EGSnrc,crcrewso/EGSnrc,mchamberland/EGSnrc,nrc-cnrc/EGSnrc,nrc-cnrc/EGSnrc,nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc,crcrewso/EGSnrc,mchamberland/EGSnrc,mchamberland/EGSnrc,mchamberland/EGSnrc,MartinMartinov/EGSnrc,mchamberland/EGSnrc,nrc-cnrc/EGSnrc,MartinMartinov/EGSnrc,MartinMartinov/EGSnrc,crcrewso/EGSnrc