Convert: Remove ConvertToOutputForExisting overload

It is no longer used.

Source/cmOutputConverter.cxx

@@ -46,19 +46,6 @@ std::string cmOutputConverter::ConvertToOutputForExisting(
   return this->ConvertToOutputFormat(remote, format);
 }
 
-std::string cmOutputConverter::ConvertToOutputForExisting(
-  RelativeRoot remote, OutputFormat format) const
-{
-  // The relative root must have a path (i.e. not FULL or NONE)
-  assert(remote != FULL);
-  assert(remote != NONE);
-
-  const char* remotePath = this->GetRelativeRootPath(remote);
-  assert(remotePath != CM_NULLPTR);
-
-  return this->ConvertToOutputForExisting(remotePath, format);
-}
-
 const char* cmOutputConverter::GetRelativeRootPath(RelativeRoot relroot) const
 {
   switch (relroot) {

Source/cmOutputConverter.h

@@ -69,11 +69,6 @@ public:
   std::string ConvertToOutputForExisting(const std::string& remote,
                                          OutputFormat format = SHELL) const;
 
-  /** For existing path identified by RelativeRoot convert to output
-      path and short path if spaces.  */
-  std::string ConvertToOutputForExisting(RelativeRoot remote,
-                                         OutputFormat format = SHELL) const;
-
   void SetLinkScriptShell(bool linkScriptShell);
 
   /**