Fix ResourceWarning in python_merge_intermediate_installation_images().
(Patch by Arfrever. Backported from Progress Overlay.)
--- python.eclass
+++ python.eclass
@@ -1983,7 +1983,9 @@
 	# Python 2
 	stdout = sys.stdout
 
-files = set(open('${T}/python_wrapper_scripts', 'rb').read().rstrip(${b}'\x00').split(${b}'\x00'))
+python_wrapper_scripts_file = open('${T}/python_wrapper_scripts', 'rb')
+files = set(python_wrapper_scripts_file.read().rstrip(${b}'\x00').split(${b}'\x00'))
+python_wrapper_scripts_file.close()
 
 for file in sorted(files):
 	stdout.write(file)