This fixes a read overflow with Sieve environment extension accessing a
bare prefix, which might have ended up causing a crash. Currently, this
affected only attempting to access "vnd.dovecot.config" environment.

With set -e, the script ends on any nonzero exit code and that would
leave the valgrind output unchecked. Fix the exit code capture so
valgrind output is correctly shown.

Found by Lintian

This commit removes the previously deprecated and now fully dropped
src_pos_r parameter from the base64_decode() function calls.

This also drops the trailing period from the log message, which matches the
changes to core.

This enables race-free kicking using socket+SIGTERM.

Pass IP structure to URL API instead of only the hostname as a string.

managesieve-login: managesieve-proxy - Allow parsing AUTHENTICATE response codes other than TRYLATER.

Fixes argument list too long error.