Which avoids passing zero lines to fpi_assemble_lines()
"gmem.c:130: failed to allocate 18446744073709551612 bytes"
#3 0x00007fe4f6ef428f in g_log (log_domain=log_domain@entry=0x7fe4f6f3506e "GLib", log_level=log_level@entry=G_LOG_LEVEL_ERROR, format=format@entry=0x7fe4f6f3e610 "%s: failed to allocate %lu bytes") at gmessages.c:1398
#4 0x00007fe4f6ef2ac4 in g_malloc0 (n_bytes=n_bytes@entry=18446744073709551612) at gmem.c:129
#5 0x00007fe4f8052020 in median_filter (filtersize=25, size=-1, data=0x0) at assembling.c:309
#6 fpi_assemble_lines (ctx=ctx@entry=0x7fe4f82ac3c0 <assembling_ctx>, lines=0x0, lines_len=0) at assembling.c:389
#7 0x00007fe4f805f3db in submit_image (ssm=ssm@entry=0x16c3cba360, data=data@entry=0x16c3cb9cc0) at drivers/vfs5011.c:412
See https://bugzilla.redhat.com/show_bug.cgi?id=1484812Closes: #42