Merge banch 5.5 till revision :
fdd6c111 - MDEV-7419 Function cli_safe_read not exported

Conflicts:
	.bzrignore
	debian/dist/Debian/mariadb-galera-server-5.5.files.in
	debian/dist/Ubuntu/mariadb-galera-server-5.5.files.in
	storage/tokudb/CMakeLists.txt
	support-files/build-tags

Start the client API for low-level protocol access:
* unsigned long mysql_net_read_packet(MYSQL *mysql);
* unsigned long mysql_net_field_length(unsigned char **packet);

* fix /etc/init.d/mysql to use log-basename for pid-filename
* fix mysqld_safe not to force logging-to-file when log-basename is specified

include oqgraph into deb packages conditionally, just like we do with tokudb

Do not use merge_for_insert for commands which use SELECT because optimizer can't work with such tables.

Fixes which makes multi-delete working with normally merged views.

    When the distance in ST_BUFFER is too far negative the coordinates can run out of the operational
    area. We should just return an empty geometry in this case.

The testcase fails randomly due to ibuf merge happening in the background.
Fix not to do any merges with ibuf_debug enabled.

Previously IF NOT EXISTS was added in Debian version in revno 3543. 
Now added the same for Ubuntu.

MDEV-7435 Windows debug: Run-Time Check Failure #3 - The variable 'unused' is being used without being initialized.
Fixed as it's done in 10.0.

causes server crash

Analysis: If wrong data types used on foreign constraint there
was possibility that foreign->id is NULL when incorrect
foreign constraint was removed from the dictionary cache.

Fix: Add guard foreign->id != NULL before trying to lookup
or remove the foreign constraint from dictionary cache.

Tested using user database where problem was repeatable.

MDEV-7055: MySQL#74664 - InnoDB: Failing assertion: len <= col->len || col->mtype == 5 || (col->len == 0 && col->mtype == 1) in file rem0rec.cc line 845

Debug assertion maybe too strict.

Analysis: Purge thread does not have thd and no access to
handlerton.

Fix: If thd does not exists we use sql_print_warning instead
of push_warning_printf.

added a script to regenerate certificates easily in the future (2035!)
restored server8k-key.pem to actually be 8K key, as it was supposed to

Backport from mysql 5.7. The patch reviewed, test added.

Added a SESSION-only system variable "wsrep_dirty_reads" to allow SELECT
queries to pass even when the node is not prepared to accept queries
(wsrep_ready=OFF). Added a test case.

At session scope, allow binlog_format to be changed to
values other than ROW with a warning.

Backport from 10.1.