ProjectQuirks moved into its own file in gnulib because one cannot
import modules with hyphens in them. Adjust the quirks file to
reflect this reality.
The ChangeLog automation scripts were incorporated in gnulib as
vcs-to-changelog for a while now since other projects expressed the
desire to use and extend this script. In the interest of avoiding
duplication of code, drop the glibc version of gitlog-to-changelog and
use the gnulib one directly.
The only file that remains is vcstocl_quirks.py, which specifies
properties and quirks of the glibc project source code. This patch
also drops the shebang at the start of vcstocl_quirks.py since the
file is not intended to be directly executable.