Flags off-centre on spy sabotage map

The flags aren't quite centered on planets when sabotaging planets.

• 1oom: 1oom_pic_002.pcx
• moo1: orion_001
• 1oom "continue" savegame - sabotage on Next Turn: 1oom_save7.bin

1oom v0.9-27-g0e0777b: main:game ui:classic hw:sdl2 os:win32