[linux-lvm] lvm filter regex format

[matthew patton]

>    https://github.com/jthornber/lvm2-ejt/blob/master/libdm/regex/parse_rx.h
 
not to be ungrateful but why on earth would one NOT use the glibc standard regex library? Nobody cares about pointless optimization. Surprises like "well, we only implemented most of the spec" are what drives people nuts!

I agree this particular length-based match is rather odd but there are plenty of useful examples I am sure that could benefit from {x,y} notation.