Continuation of 79c3c16dcb. Systemd 229
sets the default RLIMIT_CORE to infinity, causing systems to be
littered with core dumps when systemd.coredump.enable is disabled.
This restores the 15.09 soft limit of 0 and hard limit of infinity.
Systemd 229 sets kernel.core_pattern to "|/bin/false" by default,
unless systemd-coredump is enabled. Revert back to the default of
writing "core" in the current directory.
