cmComputeLinkInformation: Do not mark interface library as a path

The empty string we add as a link item for an INTERFACE_LIBRARY target
is not a path, so do not mark it as such.  The generators currently
tolerate it either way, but only by accident.

Source/cmComputeLinkInformation.cxx

@@ -655,7 +655,7 @@ void cmComputeLinkInformation::AddItem(std::string const& item,
       // Add the interface library as an item so it can be considered as part
       // of COMPATIBLE_INTERFACE_ enforcement.  The generators will ignore
       // this for the actual link line.
-      this->Items.push_back(Item(std::string(), true, tgt));
+      this->Items.push_back(Item(std::string(), false, tgt));
       }
     else
       {