PVS-Studio warning V517 for VTK

static void vprocess(FILE *fid) {
  char *s;
  ...
  if (*s == 'I' || *s == 'i') {         <<<---
    linvers = 1;
    ++s;
  } else if (*s == 'I' || *s == 'i') {  <<<---
    linvers = 0;
    ++s;
  } else
  ...
}

This suspicious code was found in VTK project by PVS-Studio static code analyzer.
Warning message is:
V517 The use of 'if (A) {...} else if (A) {...}' pattern was detected. There is a probability of logical error presence. Check lines: 224, 227. lproj lproj.c 224

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/