avoid FileExistsError on build dir

Author: lfagundes

solid_node/node/base.py

@@ -301,7 +301,10 @@ def _make_build_dirs(self):
             build_dirs.append(path.pop(0))
             build_dir = '/'.join(build_dirs)
             if not os.path.exists(build_dir):
-                os.mkdir(build_dir)
+                try:
+                    os.mkdir(build_dir)
+                except FileExistsError:
+                    pass
 
 
 class StlRenderStart(Exception):