MSVC: Fix Elvis operator

Error example:

  gost_md.c(54,45): error C2059: syntax error: ':'
  gost_md.c(67,5): error C2059: syntax error: 'if'
  gost_md.c(69,6): error C2143: syntax error: missing '{' before '->'
  gost_md.c(69,6): error C2059: syntax error: '->'
  gost_md.c(70,5): error C2059: syntax error: 'return'
  gost_md.c(71,1): error C2059: syntax error: '}'

Signed-off-by: Vitaly Chikunov <vt@altlinux.org>