Always ensure /run/finit/system exists before saving runtime service

This fixes the regression in the tests, which runs in a very stripped
down world without tmpfiles.d etc.

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

src/conf.c

@@ -471,6 +471,7 @@ void conf_save_service(int type, char *cfg, char *file)
 	svc_t foo;
 	FILE *fp;
 
+	mkpath(FINIT_RUNPATH_, 0755);
 	snprintf(fn, sizeof(fn), "%s/%s", FINIT_RUNPATH_, file);
 	if (fexist(fn))
 		warn("File %s already exists, overwriting.", fn);