Fix issue with merging
Created by: szarsti
The issue caused follogin errors to be logged in console:
{{function_clause,[{mmath_bin,merge,[<<254,1,0,122,1,0>>,<<0,0,0,0,0,0,0,0,0,0,0,...,0,0>>,<<224,18,0,0,254,1,0,254,1,0,254,1,0,....,254,1,0>>],
[{file,"/data/jenkins/workspace/dalmatinerdb/_build/default/lib/mmath/src/mmath_bin.erl"},{line,126}]},
{lists,foldl,3,[{file,"lists.erl"},{line,1262}]},
{dalmatiner_read_fsm,merge_,2,[{file,"/data/jenkins/workspace/dalmatinerdb/_build/deb/lib/dalmatiner_db/src/dalmatiner_read_fsm.erl"},{line,300}]},
{dalmatiner_read_fsm,finalize,2,[{file,"/data/jenkins/workspace/dalmatinerdb/_build/deb/lib/dalmatiner_db/src/dalmatiner_read_fsm.erl"},{line,217}]},
{gen_fsm,handle_msg,7,[{file,"gen_fsm.erl"},{line,518}]},
{proc_lib,init_p_do_apply,3,[{file,"proc_lib.erl"},{line,240}]}]},
...