eal: create runtime dir even when shared data is not used

eal: create runtime dir even when shared data is not used

When multi-process is not wanted and DPDK is run with the "no-shconf"
flag, the telemetry library still needs a runtime directory to place the
unix socket for telemetry connections. Therefore, rather than not
creating the directory when this flag is set, we can change the code to
attempt the creation anyway, but not error out if it fails. If it
succeeds, then telemetry will be available, but if it fails, the rest of
DPDK will run without telemetry. This ensures that the "in-memory" flag
will allow DPDK to run even if the whole filesystem is read-only, for
example.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>