misc: adding missing file close() calls

Spotted by Victor Stinner <victor.stinner@haypocalc.com>

mercurial/ignore.py

@@ -78,6 +78,7 @@ def ignore(root, files, warn):
             pats[f] = []
             fp = open(f)
             pats[f], warnings = ignorepats(fp)
+            fp.close()
             for warning in warnings:
                 warn("%s: %s\n" % (f, warning))
         except IOError, inst:

mercurial/revlog.py

@@ -800,6 +800,7 @@ class revlog(object):
         readahead = max(65536, length)
         df.seek(offset)
         d = df.read(readahead)
+        df.close()
         self._addchunk(offset, d)
         if readahead > length:
             return d[:length]

mercurial/ui.py

@@ -79,6 +79,7 @@ class ui(object):
 
         try:
             cfg.read(filename, fp, sections=sections, remap=remap)
+            fp.close()
         except error.ConfigError, inst:
             if trusted:
                 raise