lib-sieve: Rename sieve-settings to sieve-settings.old

src/lib-sieve/Makefile.am

src/lib-sieve/plugins/duplicate/ext-duplicate-common.c

src/lib-sieve/plugins/editheader/ext-editheader-common.c

src/lib-sieve/plugins/enotify/mailto/ntfy-mailto.c

src/lib-sieve/plugins/include/ext-include-common.c

...ib-sieve/plugins/spamvirustest/ext-spamvirustest-common.c

src/lib-sieve/plugins/subaddress/ext-subaddress.c

src/lib-sieve/plugins/vacation/ext-vacation-common.c

src/lib-sieve/plugins/variables/ext-variables-common.c

...ugins/vnd.dovecot/environment/ext-vnd-environment-items.c

src/lib-sieve/sieve-actions.c

src/lib-sieve/sieve-address-source.c

src/lib-sieve/sieve-extensions.c

src/lib-sieve/sieve-plugins.c

src/lib-sieve/sieve-script.c

src/lib-sieve/sieve-settings.old.c

src/lib-sieve/sieve-settings.old.h

src/lib-sieve/sieve-storage-sync.c

src/lib-sieve/sieve-storage.c

src/lib-sieve/sieve.c