phase-shelve: correct unicode string to honor 'shelve.store=internal'

In the case of strip-based shelves, there should be no hidden commit found.
That's because shelve.store=internal is necessary but not sufficient to enable
phase-based shelves; internal-phase must also be set.

mercurial/configitems.py

@@ -1454,7 +1454,7 b' coreconfigitem('
 coreconfigitem(
     b'shelve',
     b'store',
-    default='internal',
+    default=b'internal',
     experimental=True,
 )
 coreconfigitem(

mercurial/shelve.py

@@ -102,7 +102,7 b' class ShelfDir:'
 def _use_internal_phase(repo):
     return (
         phases.supportinternal(repo)
-        and repo.ui.config(b'shelve', b'store') == 'internal'
+        and repo.ui.config(b'shelve', b'store') == b'internal'
     )
 
 

tests/test-shelve.t

@@ -1605,3 +1605,16 b' shelve --list --patch should work even w'
   default.patch
   default.shelve
   $ hg unshelve -q
+
+Override the disabling, re-enabling phase-based shelves
+
+  $ hg shelve --config shelve.store=internal -q
+
+#if phasebased
+  $ hg log --hidden --template '{user}\n'
+  shelve@localhost
+#endif
+
+#if stripbased
+  $ hg log --hidden --template '{user}\n'
+#endif