Werror=deprecated-copy in libswoc, Werror=pessimizing-move

Updated libswoc to a dev 1.2.9 version which has a fix for
an implicit deprecated-copy constructor.

GCC 9 complains about returning with std::move for local variables
because it short circuits copy elision.

Sconstruct

@@ -37,7 +37,7 @@ if path_nghttp2 is not None:
   custom_rpath.append(path_nghttp2 + "/lib")
 SetOptionDefault("RPATH",  custom_rpath)
 
-Part("code/libswoc.part",vcs_type=VcsGit(server="github.com", repository="SolidWallOfCode/libswoc", tag="1.2.3"), package_group="proxy-verifier")
+Part("code/libswoc.part",vcs_type=VcsGit(server="github.com", repository="SolidWallOfCode/libswoc", tag="dev-1-2-9"), package_group="proxy-verifier")
 
 
 Part("local/parts/proxy-verifier.part", package_group="proxy-verifier")

local/src/client/verifier-client.cc

@@ -147,7 +147,7 @@ ClientReplayFileHandler::ssn_open(YAML::Node const &node)
         parse_for_protocol_node(protocol_sequence_node, YAML_SSN_PROTOCOL_TLS_NAME);
     if (!tls_node.is_ok()) {
       errata.note(std::move(tls_node.errata()));
-      return std::move(errata);
+      return errata;
     }
     if (tls_node.result().IsDefined()) {
       _ssn->is_tls = true;
@@ -162,7 +162,7 @@ ClientReplayFileHandler::ssn_open(YAML::Node const &node)
       auto const verify_mode = parse_verify_mode(tls_node);
       if (!verify_mode.is_ok()) {
         errata.note(std::move(verify_mode.errata()));
-        return std::move(errata);
+        return errata;
       }
       if (verify_mode > 0) {
         _ssn->_client_verify_mode = verify_mode;
@@ -173,7 +173,7 @@ ClientReplayFileHandler::ssn_open(YAML::Node const &node)
         parse_for_protocol_node(protocol_sequence_node, YAML_SSN_PROTOCOL_HTTP_NAME);
     if (!http_node.is_ok()) {
       errata.note(std::move(http_node.errata()));
-      return std::move(errata);
+      return errata;
     }
     if (http_node.result().IsDefined() &&
         http_node.result()[YAML_SSN_PROTOCOL_VERSION].Scalar() == "2") {
@@ -204,7 +204,7 @@ ClientReplayFileHandler::ssn_open(YAML::Node const &node)
     }
   }
 
-  return std::move(errata);
+  return errata;
 }
 
 swoc::Errata
@@ -226,7 +226,7 @@ ClientReplayFileHandler::txn_open(YAML::Node const &node)
         YAML_PROXY_RSP_KEY);
   }
   if (!errata.is_ok()) {
-    return std::move(errata);
+    return errata;
   }
   LoadMutex.lock();
   return {};