unit: rename BindTo= to BindsTo=

all other dependencies are in 3rd person. Change BindTo= accordingly to
BindsTo=.

Of course, the dependency is widely used, hence we parse the old name
too for compatibility.

src/cryptsetup/cryptsetup-generator.c

@@ -124,7 +124,7 @@ static int create_disk(
                 "SourcePath=/etc/crypttab\n"
                 "Conflicts=umount.target\n"
                 "DefaultDependencies=no\n"
-                "BindTo=%s dev-mapper-%%i.device\n"
+                "BindsTo=%s dev-mapper-%%i.device\n"
                 "After=systemd-readahead-collect.service systemd-readahead-replay.service %s\n"
                 "Before=umount.target\n",
                 d, d);