[REVIEW][3-5] fix STL assertion in vcl graphite code

[Michael Stahl]

this patch fixes a STL assertion in GraphiteLayout::expandOrCondense;
since i don't know how the multitude of arrays in there are supposed to
be used, i thought it's probably a good idea to check the size of the
array that will be indexed in the next line, as opposed to one that
isn't mentioned in the block...

in case this is the right fix, it should be applied to libreoffice-3-5,
and possibly libreoffice-3-4 as well (haven't checked).

http://cgit.freedesktop.org/libreoffice/core/commit/?id=d066f7e4afb3c9e395932ba7bf8715ad0770bcdd