- Fixed compiler warning for unreferenced ret in md_file() when POLARSSL_FS_IO not declared

diff --git a/include/polarssl/md.h b/include/polarssl/md.h
index f62ef20..88596cb 100644
--- a/include/polarssl/md.h
+++ b/include/polarssl/md.h
@@ -42,8 +42,7 @@
 #define POLARSSL_ERR_MD_FEATURE_UNAVAILABLE                -0x5080  /**< The selected feature is not available. */
 #define POLARSSL_ERR_MD_BAD_INPUT_DATA                     -0x5100  /**< Bad input parameters to function. */
 #define POLARSSL_ERR_MD_ALLOC_FAILED                       -0x5180  /**< Failed to allocate memory. */
-#define POLARSSL_ERR_MD_FILE_OPEN_FAILED                   -0x5200  /**< Opening of file failed. */
-#define POLARSSL_ERR_MD_FILE_READ_FAILED                   -0x5280  /**< Failure when reading from file. */
+#define POLARSSL_ERR_MD_FILE_IO_ERROR                      -0x5200  /**< Opening or reading of file failed. */
 
 typedef enum {
     POLARSSL_MD_NONE=0,