py3: slice over bytes or use .startswith() to prevent getting ascii values

Differential Revision: https://phab.mercurial-scm.org/D2457

mercurial/archival.py

@@ -154,7 +154,7 b' class tarit(object):'
 
         def taropen(mode, name='', fileobj=None):
             if kind == 'gz':
-                mode = mode[0]
+                mode = mode[0:1]
                 if not fileobj:
                     fileobj = open(name, mode + 'b')
                 gzfileobj = self.GzipFileWithTime(name, mode + 'b',

mercurial/patch.py

@@ -2518,7 +2518,7 b' def difflabel(func, *args, **kw):'
                                 yield (t, l)
                         else:
                             for token in tabsplitter.findall(stripline):
-                                if '\t' == token[0]:
+                                if token.startswith('\t'):
                                     yield (token, 'diff.tab')
                                 else:
                                     yield (token, label)