fix(treewide): fix incorrect usage of std::move

`auto &&` and `T &&` are forwarding references and can be
either lvalue or rvalue references. Moving from universal references
is incorrect and should not be done.

Moving from integral or floating-point values is pointless and just
worsens debug performance.

src/libstore/filetransfer.cc

@@ -153,7 +153,7 @@ struct curlFileTransfer : public FileTransfer
         template<class T>
         void fail(T && e)
         {
-            failEx(std::make_exception_ptr(std::move(e)));
+            failEx(std::make_exception_ptr(std::forward<T>(e)));
         }
 
         LambdaSink finalSink;

src/libstore/machines.cc

@@ -33,7 +33,7 @@ Machine::Machine(
     systemTypes(systemTypes),
     sshKey(sshKey),
     maxJobs(maxJobs),
-    speedFactor(speedFactor == 0.0f ? 1.0f : std::move(speedFactor)),
+    speedFactor(speedFactor == 0.0f ? 1.0f : speedFactor),
     supportedFeatures(supportedFeatures),
     mandatoryFeatures(mandatoryFeatures),
     sshPublicHostKey(sshPublicHostKey)

src/libutil/executable-path.cc

@@ -35,7 +35,7 @@ ExecutablePath ExecutablePath::parse(const OsString & path)
         std::make_move_iterator(strings.begin()),
         std::make_move_iterator(strings.end()),
         std::back_inserter(ret),
-        [](auto && str) {
+        [](OsString && str) {
             return fs::path{
                 str.empty()
                     // "A zero-length prefix is a legacy feature that