remove meta class access specifiers as they are not supported in MATLAB < R2012a

Revert when minimum supported Matlab version >= R2012a
3 jobs for master in 1 minute and 8 seconds
Status Job ID Name Coverage
  Test
passed #8205
test_matlab

00:00:26

passed #8207
test_octave

00:01:06

passed #8206
test_old_matlab

00:00:24