networkd: rename manager_connect_varlink() → manager_varlink_init()

This function doesn't "connect" to Varlink (i.e. it isn't a client) but
it binds a Varlink socket (i.e. it is server), hence let's remove the
verb "connect" from its name. let's copy how machined/resolved name the
counterpart for this function: manager_varlink_init()

src/network/networkd-manager-varlink.c

@@ -279,9 +279,9 @@ static int vl_method_set_persistent_storage(sd_varlink *vlink, sd_json_variant *
         return sd_varlink_reply(vlink, NULL);
 }
 
-int manager_connect_varlink(Manager *m, int fd) {
+int manager_varlink_init(Manager *m, int fd) {
         _cleanup_(sd_varlink_server_unrefp) sd_varlink_server *s = NULL;
-        _unused_ _cleanup_close_ int fd_close = fd;
+        _unused_ _cleanup_close_ int fd_close = fd; /* take possession */
         int r;
 
         assert(m);

src/network/networkd-manager-varlink.h

@@ -3,4 +3,4 @@
 
 #include "networkd-forward.h"
 
-int manager_connect_varlink(Manager *m, int fd);
+int manager_varlink_init(Manager *m, int fd);

src/network/networkd-manager.c

@@ -595,7 +595,7 @@ int manager_setup(Manager *m) {
         if (m->test_mode)
                 return 0;
 
-        r = manager_connect_varlink(m, TAKE_FD(varlink_fd));
+        r = manager_varlink_init(m, TAKE_FD(varlink_fd));
         if (r < 0)
                 return r;