update-my-copyright.pl: update to git releases that don't prefix git status output with # by default anymore
core: switch more printf(stderr) to unique messages that can be silenced with HWLOC_HIDE_ERRORS=1

Useful when debugging failures to merge because of different OS indexes or levels.
linux/NUMA: Work around buggy NUMA node cpusets

If Linux reports multiple nodes with intersecting (or identical) cpusets,
they get merged and the Linux backend asserts false.

Don't assert when insertion returns a merge error anymore.
Just disable NUMA distances if that ever happens since one
object is missing (instead of removing the corresponding row/column).
The BIOS is buggy, the matrix would likely be meaningless anyway.

Thanks to Jeff Becker for reporting the problem on the OMPI list.

By the way, fix the number of nodes returned by look_sysfsnode()
when we failed to read/create some NUMA objects.
tests/linux: add a test with very buggy NUMA info

Linux reports 8 NUMA nodes containing the (same) entire list of all cores,
hence all of them get merged.

Thanks to Jeff Becker for the test case.