httppeer: use %s for formatting

httppeer: use %s for formatting

This prevents a b'' from appearing in Python 3 output. We keep the
single quotes for backwards compatibility.

Differential Revision: https://phab.mercurial-scm.org/D5647

--- a/mercurial/httppeer.py	Tue Jan 22 16:54:56 2019 -0800
+++ b/mercurial/httppeer.py	Tue Jan 22 16:58:48 2019 -0800
@@ -816,8 +816,8 @@
             return
 
         raise error.CapabilityError(
-            _('cannot %s; client or remote repository does not support the %r '
-              'capability') % (purpose, name))
+            _('cannot %s; client or remote repository does not support the '
+              '\'%s\' capability') % (purpose, name))
 
     # End of ipeercapabilities.
 

--- a/mercurial/repository.py	Tue Jan 22 16:54:56 2019 -0800
+++ b/mercurial/repository.py	Tue Jan 22 16:58:48 2019 -0800
@@ -346,8 +346,8 @@
             return
 
         raise error.CapabilityError(
-            _('cannot %s; remote repository does not support the %r '
-              'capability') % (purpose, name))
+            _('cannot %s; remote repository does not support the '
+              '\'%s\' capability') % (purpose, name))
 
 class iverifyproblem(interfaceutil.Interface):
     """Represents a problem with the integrity of the repository.