[BUGFIX] Add SQL-comparator <> to SQL parser

Comparator != was supported before.
But <> is ANSI SQL and therefore should be
supported as well.

Change-Id: I49dde6f06715ecd33df044d8a2e85a813516d6ad
Fixes: #32626
Releases: 4.4, 4.5, 4.6, 4.7
Reviewed-on: http://review.typo3.org/7325
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers