windowsrtinstall: Fix errors on vcredist not being present before install.
windowsrtinstall: Fix errors on vcredist not being present before install.

We install the 2013 VC redistributables, but we first read the registry to
determine if they were already installed.  That registry read returns an
error if they aren't already present.  So, we clear the error after reading
the registry.  We also added the 32-bit 2013 VC redistributables to the
64-bit OS install, just to be safe.

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools