templater: take cStringIO out of indent

mercurial/templater.py

@@ -256,16 +256,17 b' def shortdate(date):'
 
 def indent(text, prefix):
     '''indent each non-empty line of text after first with prefix.'''
-    fp = cStringIO.StringIO()
     lines = text.splitlines()
     num_lines = len(lines)
+    def indenter():
     for i in xrange(num_lines):
         l = lines[i]
-        if i and l.strip(): fp.write(prefix)
-        fp.write(l)
+            if i and l.strip():
+                yield prefix
+            yield l
         if i < num_lines - 1 or text.endswith('\n'):
-            fp.write('\n')
-    return fp.getvalue()
+                yield '\n'
+    return "".join(indenter())
 
 common_filters = {
     "addbreaks": nl2br,