PVS-Studio warning V617 for ABackup

#define FILE_ATTRIBUTE_READONLY 0x00000001

BOOL DeleteAnyFile( char* cFileName ) {
  ....
  if ( nAttr | FILE_ATTRIBUTE_READONLY ) {
    nAttr &= ~FILE_ATTRIBUTE_READONLY ;
    SetFileAttributes( cFileName, nAttr ) ;
  }
  ....
}

This suspicious code was found in ABackup project by PVS-Studio static code analyzer.
Warning message is:
V617 Consider inspecting the condition. The '0x00000001' argument of the '|' bitwise operation contains a non-zero value. kitcpp.cpp 304

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/