Fixed primary equivalence classes, so that delimiter based sort keys with a delim in position 0 still work.

[SVN r26738]

libs/regex

@@ -1 +1 @@
-Subproject commit 2a248d1f8746155378db81037db306ffce9cdc0c
+Subproject commit 8545aeb1f32b266fca026562b3eea1c21fe5bce3