win32: Fix compilation warnings from commit 40c921f8

connect.c:953:5: warning: initializer element is not computable at load
                 time
connect.c:953:5: warning: missing initializer for field 'dwMinorVersion'
                 of 'OSVERSIONINFOEX'
curl_sspi.c:97:5: warning: initializer element is not computable at load
                  time
curl_sspi.c:97:5: warning: missing initializer for field 'szCSDVersion'
                  of 'OSVERSIONINFOEX'