Fix iv_len interface.

cipher_info->iv_size == 0 is no longer ambiguous, and
cipher_get_iv_size() always returns something useful to generate an IV.
diff --git a/library/cipher_wrap.c b/library/cipher_wrap.c
index 5c98100..ebe60cf 100644
--- a/library/cipher_wrap.c
+++ b/library/cipher_wrap.c
@@ -150,6 +150,7 @@
     128,
     "AES-128-CBC",
     16,
+    0,
     16,
     &aes_info
 };
@@ -160,6 +161,7 @@
     192,
     "AES-192-CBC",
     16,
+    0,
     16,
     &aes_info
 };
@@ -170,6 +172,7 @@
     256,
     "AES-256-CBC",
     16,
+    0,
     16,
     &aes_info
 };
@@ -181,6 +184,7 @@
     128,
     "AES-128-CFB128",
     16,
+    0,
     16,
     &aes_info
 };
@@ -191,6 +195,7 @@
     192,
     "AES-192-CFB128",
     16,
+    0,
     16,
     &aes_info
 };
@@ -201,6 +206,7 @@
     256,
     "AES-256-CFB128",
     16,
+    0,
     16,
     &aes_info
 };
@@ -213,6 +219,7 @@
     128,
     "AES-128-CTR",
     16,
+    0,
     16,
     &aes_info
 };
@@ -223,6 +230,7 @@
     192,
     "AES-192-CTR",
     16,
+    0,
     16,
     &aes_info
 };
@@ -233,6 +241,7 @@
     256,
     "AES-256-CTR",
     16,
+    0,
     16,
     &aes_info
 };
@@ -271,7 +280,8 @@
     POLARSSL_MODE_GCM,
     128,
     "AES-128-GCM",
-    0,
+    12,
+    1,
     16,
     &gcm_aes_info
 };
@@ -281,7 +291,8 @@
     POLARSSL_MODE_GCM,
     256,
     "AES-256-GCM",
-    0,
+    12,
+    1,
     16,
     &gcm_aes_info
 };
@@ -373,6 +384,7 @@
     128,
     "CAMELLIA-128-CBC",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -383,6 +395,7 @@
     192,
     "CAMELLIA-192-CBC",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -393,6 +406,7 @@
     256,
     "CAMELLIA-256-CBC",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -404,6 +418,7 @@
     128,
     "CAMELLIA-128-CFB128",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -414,6 +429,7 @@
     192,
     "CAMELLIA-192-CFB128",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -424,6 +440,7 @@
     256,
     "CAMELLIA-256-CFB128",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -436,6 +453,7 @@
     128,
     "CAMELLIA-128-CTR",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -446,6 +464,7 @@
     192,
     "CAMELLIA-192-CTR",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -456,6 +475,7 @@
     256,
     "CAMELLIA-256-CTR",
     16,
+    0,
     16,
     &camellia_info
 };
@@ -581,6 +601,7 @@
     POLARSSL_KEY_LENGTH_DES,
     "DES-CBC",
     8,
+    0,
     8,
     &des_info
 };
@@ -603,6 +624,7 @@
     POLARSSL_KEY_LENGTH_DES_EDE,
     "DES-EDE-CBC",
     8,
+    0,
     8,
     &des_ede_info
 };
@@ -625,6 +647,7 @@
     POLARSSL_KEY_LENGTH_DES_EDE3,
     "DES-EDE3-CBC",
     8,
+    0,
     8,
     &des_ede3_info
 };
@@ -709,6 +732,7 @@
     128,
     "BLOWFISH-CBC",
     8,
+    0,
     8,
     &blowfish_info
 };
@@ -720,6 +744,7 @@
     128,
     "BLOWFISH-CFB64",
     8,
+    0,
     8,
     &blowfish_info
 };
@@ -732,6 +757,7 @@
     128,
     "BLOWFISH-CTR",
     8,
+    0,
     8,
     &blowfish_info
 };
@@ -781,6 +807,7 @@
     128,
     "ARC4-128",
     0,
+    0,
     1,
     &arc4_base_info
 };
@@ -834,6 +861,7 @@
     0,
     "NULL",
     0,
+    0,
     1,
     &null_base_info
 };