util-lib: split out syslog-related calls into syslog-util.[ch]

src/shared/bus-util.c

@@ -44,6 +44,7 @@
 #include "signal-util.h"
 #include "string-util.h"
 #include "strv.h"
+#include "syslog-util.h"
 #include "unit-name.h"
 #include "utf8.h"
 #include "util.h"

src/shared/conf-parser.c

@@ -39,6 +39,7 @@
 #include "strv.h"
 #include "utf8.h"
 #include "util.h"
+#include "syslog-util.h"
 
 int config_item_table_lookup(
                 const void *table,