mod_sndfile: update pos on the file handle on reads (MODFORM-33)

git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@14377 d0543943-73ff-0310-b7d9-9358b9ac24b2

src/mod/formats/mod_sndfile/mod_sndfile.c

@@ -257,6 +257,7 @@ static switch_status_t sndfile_file_read(switch_file_handle_t *handle, void *dat
 		*len = (size_t) sf_readf_int(context->handle, (int *) data, inlen);
 	}
 
+	handle->pos += *len;
 	handle->sample_count += *len;
 
 	return *len ? SWITCH_STATUS_SUCCESS : SWITCH_STATUS_FALSE;