[Libreoffice] [REVIEW] fix for fdo#41807 crash with ROW() or COLUMN() in matrix formulas

[Markus Mohrhard]

Hey,

http://cgit.freedesktop.org/libreoffice/core/commit/?id=cf0dd2113527ba0a601c5c59de7f7f44da161d21
fixes a crash that happens if you use ROW() or COLUMN() in a matrix
function. We try to get an entry from an empty mdds container which
results in a crash.

Even that we are not sure that return true is always correct this
patch should be safe since this only matters in the case where a crash
would have happened.

Review and sign-off appreciated.

Markus