remove rsyncdir usage since pytest-xdist has deprecated it

src/pytest_cov/engine.py

@@ -270,12 +270,6 @@ class DistMaster(CovController):
     def start(self):
         cleanup()
 
-        # Ensure coverage rc file rsynced if appropriate.
-        if self.cov_config and Path(self.cov_config).exists():
-            # rsyncdir is going away in pytest-xdist 4.0, already deprecated
-            if hasattr(self.config.option, 'rsyncdir'):
-                self.config.option.rsyncdir.append(self.cov_config)
-
         self.cov = coverage.Coverage(
             source=self.cov_source,
             branch=self.cov_branch,