move cache copy op to repository

Signed-off-by: george.ridal <george.ridal@findesign.com.au>

Author: vanridal

src/rez/package_cache.py

@@ -405,7 +405,7 @@ def _while_copying():
         th.start()
 
         try:
-            shutil.copytree(variant_root, rootpath)
+            variant.repository.cache_variant(variant, rootpath)
         finally:
             still_copying = False
 

src/rez/package_repository.py

@@ -11,6 +11,7 @@
 import threading
 import os.path
 import time
+import shutil
 
 
 def get_package_repository_types():
@@ -510,6 +511,12 @@ def _uid(self):
         """
         return (self.name(), self.location)
 
+    def cache_variant(self, variant, location):
+        """
+        Copy a variant from repository to cache location
+        """
+        shutil.copytree(variant.root, location)
+
 
 class PackageRepositoryManager(object):
     """Package repository manager.