instmods: get filenames from stdin if no args; use it

instmods: get filenames from stdin if no args; use it

Use bash  "[[ string =~ pattern ]]"  instead of "egrep -q".
Replace control-dominated serial fondling
	for var in $(proc1); do proc2 var; done
with data-dominated parallel pipeline
	proc1  |  while read var; do proc2 var; done
Together this is a large savings.

[harald@redhat.com: fixed network kernel module filter]