!73 删除枚举值，保证和官方一致

Merge pull request !73 from liyufan/l03

include/mbedtls/md.h

@@ -54,7 +54,7 @@ extern "C" {
  */
 typedef enum {
     MBEDTLS_MD_NONE=0,    /**< None. */
-    MBEDTLS_MD_MD5=3,       /**< The MD5 message digest. */
+    MBEDTLS_MD_MD5,       /**< The MD5 message digest. */
     MBEDTLS_MD_SHA1,      /**< The SHA-1 message digest. */
     MBEDTLS_MD_SHA224,    /**< The SHA-224 message digest. */
     MBEDTLS_MD_SHA256,    /**< The SHA-256 message digest. */