Remove dead code RemoteStore::sameMachine

It has been dead code since 9747ea84b4.

src/libstore/remote-store.hh

@@ -38,8 +38,6 @@ class RemoteStore : public virtual RemoteStoreConfig,
 {
 public:
 
-    virtual bool sameMachine() = 0;
-
     RemoteStore(const Params & params);
 
     /* Implementations of abstract store API methods. */

src/libstore/ssh-store.cc

@@ -49,9 +49,6 @@ public:
         return *uriSchemes().begin() + "://" + host;
     }
 
-    bool sameMachine() override
-    { return false; }
-
     // FIXME extend daemon protocol, move implementation to RemoteStore
     std::optional<std::string> getBuildLogExact(const StorePath & path) override
     { unsupported("getBuildLogExact"); }

src/libstore/uds-remote-store.hh

@@ -29,9 +29,6 @@ public:
     static std::set<std::string> uriSchemes()
     { return {"unix"}; }
 
-    bool sameMachine() override
-    { return true; }
-
     ref<FSAccessor> getFSAccessor() override
     { return LocalFSStore::getFSAccessor(); }