PVS-Studio warning V523 for WebM

static void encode_superblock(....)
{
  if (mbmi->ref_frame[0] != LAST_FRAME)
    cpi->zbin_mode_boost = GF_ZEROMV_ZBIN_BOOST;
  else
    cpi->zbin_mode_boost = LF_ZEROMV_ZBIN_BOOST;
  ....
}

This suspicious code was found in WebM project by PVS-Studio static code analyzer.
Warning message is:
V523 The 'then' statement is equivalent to the 'else' statement. vp9_encodeframe.c 2450

PVS-Studio is a static analyzer for detecting bugs in the source code of applications written in C, C++, C++11, C++/CX. Site: http://www.viva64.com/en/pvs-studio/