wrapfunction: use sysstr instead of bytes as argument in "fastannotate"

This is as valid and simpler, it will help us to eventually get ride of
`safehasattr`.

hgext/fastannotate/protocol.py

@@ -101,7 +101,7 b' def _registerwireprotocommand():'
 
 def serveruisetup(ui):
     _registerwireprotocommand()
-    extensions.wrapfunction(wireprotov1server, b'_capabilities', _capabilities)
+    extensions.wrapfunction(wireprotov1server, '_capabilities', _capabilities)
 
 
 # client-side

hgext/fastannotate/support.py

@@ -129,8 +129,8 b' def _remotefctxannotate(orig, self, foll'
 
 
 def replacehgwebannotate():
-    extensions.wrapfunction(hgweb.webutil, b'annotate', _hgwebannotate)
+    extensions.wrapfunction(hgweb.webutil, 'annotate', _hgwebannotate)
 
 
 def replacefctxannotate():
-    extensions.wrapfunction(hgcontext.basefilectx, b'annotate', _fctxannotate)
+    extensions.wrapfunction(hgcontext.basefilectx, 'annotate', _fctxannotate)