fileio: accept FILE* in addition to path in parse_env_file()

Most our other parsing functions do this, let's do this here too,
internally we accept that anyway. Also, the closely related
load_env_file() and load_env_file_pairs() also do this, so let's be
systematic.

src/shared/cgroup-show.c

@@ -344,7 +344,7 @@ int show_cgroup_get_path_and_warn(
                 const char *m;
 
                 m = strjoina("/run/systemd/machines/", machine);
-                r = parse_env_file(m, NEWLINE, "SCOPE", &unit, NULL);
+                r = parse_env_file(NULL, m, NEWLINE, "SCOPE", &unit, NULL);
                 if (r < 0)
                         return log_error_errno(r, "Failed to load machine data: %m");
 

src/shared/condition.c

@@ -464,7 +464,7 @@ static int condition_test_needs_update(Condition *c) {
                 uint64_t timestamp;
                 int r;
 
-                r = parse_env_file(p, NULL, "TIMESTAMP_NSEC", &timestamp_str, NULL);
+                r = parse_env_file(NULL, p, NULL, "TIMESTAMP_NSEC", &timestamp_str, NULL);
                 if (r < 0) {
                         log_error_errno(r, "Failed to parse timestamp file '%s', using mtime: %m", p);
                         return true;

src/shared/udev-util.c

@@ -18,7 +18,7 @@ int udev_parse_config(void) {
         size_t n;
         int r;
 
-        r = parse_env_file("/etc/udev/udev.conf", NEWLINE, "udev_log", &val, NULL);
+        r = parse_env_file(NULL, "/etc/udev/udev.conf", NEWLINE, "udev_log", &val, NULL);
         if (r == -ENOENT || !val)
                 return 0;
         if (r < 0)