Remove redundant --verify-passphrase in man.

Fixes: #938

man/cryptsetup-open.8.adoc

@@ -52,7 +52,7 @@ the keyring in plain mode. For subsequent commands (like resize), the user must
 ensure that the key in the keyring is unchanged. Otherwise, reloading the key
 can cause data corruption after an unexpected key change.
 
-*<options>* can be [--hash, --cipher, --verify-passphrase, --sector-size,
+*<options>* can be [--hash, --cipher, --sector-size,
 --key-file, --keyfile-size, --keyfile-offset, --key-size, --offset,
 --skip, --device-size, --size, --readonly, --shared, --allow-discards,
 --refresh, --timeout, --verify-passphrase, --iv-large-sectors, --volume-key-keyring].