selinux: always try to load the full selinux db

https://github.com/systemd/systemd/pull/2508#issuecomment-190901170
Maybe fixes https://bugzilla.redhat.com/show_bug.cgi?id=1308771.

src/basic/selinux-util.c

@@ -80,31 +80,23 @@ void mac_selinux_retest(void) {
 #endif
 }
 
-int mac_selinux_init(const char *prefix) {
+int mac_selinux_init(void) {
         int r = 0;
 
 #ifdef HAVE_SELINUX
         usec_t before_timestamp, after_timestamp;
         struct mallinfo before_mallinfo, after_mallinfo;
 
-        if (!mac_selinux_use())
+        if (label_hnd)
                 return 0;
 
-        if (label_hnd)
+        if (!mac_selinux_use())
                 return 0;
 
         before_mallinfo = mallinfo();
         before_timestamp = now(CLOCK_MONOTONIC);
 
-        if (prefix) {
-                struct selinux_opt options[] = {
-                        { .type = SELABEL_OPT_SUBSET, .value = prefix },
-                };
-
-                label_hnd = selabel_open(SELABEL_CTX_FILE, options, ELEMENTSOF(options));
-        } else
-                label_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
-
+        label_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
         if (!label_hnd) {
                 log_enforcing("Failed to initialize SELinux context: %m");
                 r = security_getenforce() == 1 ? -errno : 0;

src/basic/selinux-util.h

@@ -29,7 +29,7 @@ bool mac_selinux_use(void);
 bool mac_selinux_have(void);
 void mac_selinux_retest(void);
 
-int mac_selinux_init(const char *prefix);
+int mac_selinux_init(void);
 void mac_selinux_finish(void);
 
 int mac_selinux_fix(const char *path, bool ignore_enoent, bool ignore_erofs);