fix awk script check_name() in extended_bin

[sg2342]

when the argument to the system calls in check_name awk script is built, the file part must be quoted. if this is not done, the system call will fail whenever the filename contains spaces

fix #908

[sg2342]

@ferd , @tsloughter : do you want a shelltest for this?

[ferd]

if you have bandwidth for that, it would certainly be appreciated and useful.