HPCC-20499 Dafilesrv windows build break fix

The cryptohelper digisign implementations are not implemented
in WIN32 and the dafilesrv code should have been conditionally
dependent on OPENSSL _and_ WIN32 to avoid MSVC compilation issues.

Signed-off-by: Jake Smith <jake.smith@lexisnexisrisk.com>

common/remote/sockfile.cpp

@@ -4496,7 +4496,7 @@ void verifyMetaInfo(IPropertyTree &actNode, bool authorizedOnly, const IProperty
     Owned<IPropertyTree> metaInfoEnvelope = createPTree(decompressedMetaInfoMb);
 
     Owned<IPropertyTree> metaInfo;
-#ifdef _USE_OPENSSL
+#if defined(_USE_OPENSSL) && !defined(_WIN32)
     MemoryBuffer metaInfoBlob;
     metaInfoEnvelope->getPropBin("metaInfoBlob", metaInfoBlob);