Cleanup performed with the following semantic patch:

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	io_remove(&E);
	- }
	+ io_remove(&E);

	@@
	expression E;
	@@

	- if (E != NULL) {
	- 	io_remove_closed(&E);
	- }
	+ io_remove_closed(&E);

Error handling is delayed, so that we need to explicitly handle the error in Sieve.
This is now implemented by handling the error before executing the scritpt and placing the parsed address in struct sieve_script_env.

lib-sieve: Added sieve_script_env_init() to initialize struct sieve_script_env from struct mail_user.

Most code was put in an unnecessary else block.

If a home directory is given, it's assumed that it will be autocreated even
if it doesn't initially exist. Earlier the autocreation may have been done
by lib-storage as it created the mail root directory, but this no longer
happens.

The parent event doesn't really matter here, so NULL is used.

This follows the following commits in Dovecot:
lib-storage: Moved connection information in struct mail_user into separate struct mail_user_connection_data.
lib-storage: mail-user: Added more information about the client connection.

lib-sieve: vnd.dovecot.report extension: Fixed creation of "Original-Mail-From" and original "Original-Rcpt-To" headers.

Recent changes relating to lib-smtp caused the paths to have duplicate '<' '>'.

Now using struct smtp_address rather than sieve_address.
In some cases, struct message_address may prove to be more suitable, but this is the best fit for now.
Adjusted to the renamed fields in struct mail_deliver_context.

It doesn't serve a purpose either, since parsing "from" address from URI is not allowed for notify mailto.

lib-sieve: store action: Avoid NULL pointer dereference during rollback when transaction context is somehow unassigned.

This change matches the other transaction stages.
This will not currently happen though.
Reported by Coverity.

Otherwise the error status is overwritten.
Problem found by Coverity.

Used the stream's cur_header field, rather than the local variable.
Problem found by Coverity.

The merge_from_parent() function may not actually read anything, potentially leaving the stream buffer unassigned.
Problem found by Coverity.

This makes the implementation easier to understand and amend once Dovecot APIs changes.
This implicitly makes the implementation suitable for the new istream snapshot handling.

Added assertions on subtractions.
Restructured the code for clarity.
Added comments.

Ported Dovecot's istream-jsonstr for ManageSieve syntax.

Call master_login_init() before master_service_init_finish(), which frees
all the data stack done in initialization.

This didn't normally cause any visible problems, because data stack wasn't
currently being used in a way that the strings were invalidated. However,
it was causing failures if --enable-devel-checks was used.

Patch by Andreas Schulze.

Patch by Andreas Schulze.

Patch by Andreas Schulze.

lib-sieve: enotify plugin: mailto method: Make sure from header is set to a usable address and not (null).

It's replaced with fd-util.h which is automatically included now.

It's replaced with fd-util.h which is automatically included now

Mirrors imap fix in Dovecot: 42149f48624b82fdf9631c256497580154c2e412

It's impossible for the command's pointer to be NULL at this point.
Previously, the command_find() would have returned NULL, but this check
presumably short-circuits that search in the trivial case, so has some
real use.

Problem now found by GCC 7.

Problem found by GCC 7.