core: Remove explicit Plymouth integration

Even if plymouth is running, it might have not displayed the splash yet,
so we'll see a few lines on fbcon when we should have otherwise had
nothing.

Plymouth integration was added to systemd in commit
6faa11140b. That same day, Plymouth got
systemd integration [0]. As such, the Plymouth integration has always
been obsolete, and was probably only for older Plymouth's. But I can't
imagine anybody running a Plymouth from 2011 with a systemd from 2015.

Remove the Plymouth/systemd integration, and let Plymouth's code tell
systemd to print the details.

[0] http://cgit.freedesktop.org/plymouth/commit/?id=537c16422cd49f1beeaab1ad39846a00018faec1

Signed-off-by: Jasper St. Pierre <jstpierre@mecheye.net>
Cc: Daniel Drake <dsd@endlessm.com>
Cc: Ray Strode <rstrode@redhat.com>

src/shared/util.c

@@ -4228,10 +4228,6 @@ bool nulstr_contains(const char*nulstr, const char *needle) {
         return false;
 }
 
-bool plymouth_running(void) {
-        return access("/run/plymouth/pid", F_OK) >= 0;
-}
-
 char* strshorten(char *s, size_t l) {
         assert(s);
 

src/shared/util.h

@@ -549,8 +549,6 @@ int kill_and_sigcont(pid_t pid, int sig);
 
 bool nulstr_contains(const char*nulstr, const char *needle);
 
-bool plymouth_running(void);
-
 bool hostname_is_valid(const char *s) _pure_;
 char* hostname_cleanup(char *s, bool lowercase);