chansrv: sound, remove a do not know and a comment

configure.ac

@@ -238,7 +238,7 @@ fi
 if test "x$enable_fdkaac" = "xyes"
 then
   AC_CHECK_HEADER([fdk-aac/aacenc_lib.h], [],
-    [AC_MSG_ERROR([please install libfdk-aac-dev or dontknow-devel])])
+    [AC_MSG_ERROR([please install libfdk-aac-dev or fdk-aac-devel])])
 fi
 
 # checking for opus

sesman/chansrv/sound.c

@@ -520,7 +520,6 @@ sound_wave_compress_fdk_aac(char *data, int data_bytes, int *format_index)
         }
 
         aot = 2; /* MPEG-4 AAC Low Complexity. */
-        //aot = 129; /* MPEG-2 AAC Low Complexity. */
         error = aacEncoder_SetParam(g_fdk_aac_encoder, AACENC_AOT, aot);
         if (error != AACENC_OK)
         {