Update docstring for EbuildBuildDir.clean_log().

svn path=/main/trunk/; revision=13072
diff --git a/pym/_emerge/__init__.py b/pym/_emerge/__init__.py
index 2fb2003..3d7439d 100644
--- a/pym/_emerge/__init__.py
+++ b/pym/_emerge/__init__.py
@@ -2634,8 +2634,7 @@
 				portage.locks.unlockdir(catdir_lock)
 
 	def clean_log(self):
-		"""Uses shutil.rmtree() rather than spawning a 'clean' phase. Disabled
-		by keepwork or keeptemp in FEATURES."""
+		"""Discard existing log."""
 		settings = self.settings
 
 		for x in ('.logid', 'temp/build.log'):