PgBouncer Version Bump and Bug Fixes

Fixes bugs 477062 [1], 425034 [2], 460310 [3], and 425480 [4].
[1] https://bugs.gentoo.org/show_bug.cgi?id=477062
[2] https://bugs.gentoo.org/show_bug.cgi?id=425034
[3] https://bugs.gentoo.org/show_bug.cgi?id=460310
[4] https://bugs.gentoo.org/show_bug.cgi?id=425480