ext/sodium: fix pwhash_argon2i test

ext/sodium/tests/pwhash_argon2i.phpt

@@ -10,14 +10,14 @@ $passwd = 'password';
 $hash = sodium_crypto_pwhash_str
   ($passwd, SODIUM_CRYPTO_PWHASH_OPSLIMIT_INTERACTIVE,
 			SODIUM_CRYPTO_PWHASH_MEMLIMIT_INTERACTIVE);
-var_dump(substr($hash, 0, 9) ===
+var_dump(substr($hash, 0, strlen(SODIUM_CRYPTO_PWHASH_STRPREFIX)) ===
 		 SODIUM_CRYPTO_PWHASH_STRPREFIX);
 
 $testHash = '$argon2i$v=19$m=4096,t=3,p=1$MzE4ODFiZWFlMjAzOWUAAA$FWUV6tsyJ32qThiLi1cCsLIbf3dIOG/RwXcTzt536KY';
 $c = sodium_crypto_pwhash_str_verify($testHash, $passwd);
 var_dump($c);
 
-$testHash = '$argon2i$v=19$m=4096,t=2,p=1$c29tZXNhbHQAAAAAAAAAAA$JTBozgKQiCn5yKAm3Hz0vUSX/XgfqhZloNCxDWmeDr0';
+$testHash = '$argon2i$v=19$m=4096,t=0,p=1$c29tZXNhbHQAAAAAAAAAAA$JTBozgKQiCn5yKAm3Hz0vUSX/XgfqhZloNCxDWmeDr0';
 $c = sodium_crypto_pwhash_str_verify($testHash, $passwd);
 var_dump($c);