goprotobuf: Add new-style tags for r60 and weekly.2011-09-07.

Also remove the floating "release" and "weekly" tags,
since they will no longer do anything useful, if I understand correctly.

R=adg, r
CC=golang-dev
http://codereview.appspot.com/5014048

.hgtags

@@ -6,11 +6,11 @@
 89e4e9b619197f71e60c3ed309474cfd94475061 weekly.2011-07-07
 32017900448961add50b154f63d1f80907285984 weekly.2011-08-10
 c9278633d1eb1c80bc5946eb6724e2d22cd28265 weekly.2011-08-17
-c9278633d1eb1c80bc5946eb6724e2d22cd28265 weekly
 f3ef978cda6fabc10f6039aeed960340547c6d5a release.r56
 fa1080cfc0a4d0fa24844bc50124aed892365059 release.r57.1
 fa1080cfc0a4d0fa24844bc50124aed892365059 release.r57.2
 cfe37a63cede6cd072434965e6ea426b90bcb223 release.r58
 cfe37a63cede6cd072434965e6ea426b90bcb223 release.r58.1
 da17c98c73d8801baa1d2e493c9ac0844470ef0a release.r59
-da17c98c73d8801baa1d2e493c9ac0844470ef0a release
+f1f9e5a4fdf0560ca8c5067fffb70be3f38de6d1 go.r60
+f1f9e5a4fdf0560ca8c5067fffb70be3f38de6d1 go.weekly.2011-09-07