tests: gnrc_sixlowpan: fix expect for #9585
tests: gnrc_sixlowpan: fix expect for #9585

PR #9585 changed the output for the dump slightly, so now this test
is failing. This fixes that and should also fix some issues from the
2017.07 release tests.

smlng/RIOT,lazytech-org/RIOT,authmillenon/RIOT,BytesGalore/RIOT,x3ro/RIOT,OlegHahm/RIOT,biboc/RIOT,biboc/RIOT,miri64/RIOT,mfrey/RIOT,toonst/RIOT,basilfx/RIOT,toonst/RIOT,A-Paul/RIOT,RIOT-OS/RIOT,aeneby/RIOT,A-Paul/RIOT,OlegHahm/RIOT,yogo1212/RIOT,gebart/RIOT,cladmi/RIOT,josephnoir/RIOT,biboc/RIOT,lazytech-org/RIOT,mtausig/RIOT,basilfx/RIOT,ant9000/RIOT,jasonatran/RIOT,aeneby/RIOT,kbumsik/RIOT,kbumsik/RIOT,RIOT-OS/RIOT,mfrey/RIOT,josephnoir/RIOT,cladmi/RIOT,kYc0o/RIOT,rfuentess/RIOT,A-Paul/RIOT,toonst/RIOT,OlegHahm/RIOT,miri64/RIOT,kYc0o/RIOT,kbumsik/RIOT,authmillenon/RIOT,biboc/RIOT,OTAkeys/RIOT,OlegHahm/RIOT,josephnoir/RIOT,basilfx/RIOT,A-Paul/RIOT,biboc/RIOT,kYc0o/RIOT,OTAkeys/RIOT,kaspar030/RIOT,mtausig/RIOT,ant9000/RIOT,kYc0o/RIOT,aeneby/RIOT,basilfx/RIOT,gebart/RIOT,avmelnikoff/RIOT,BytesGalore/RIOT,mtausig/RIOT,OTAkeys/RIOT,yogo1212/RIOT,BytesGalore/RIOT,ant9000/RIOT,toonst/RIOT,x3ro/RIOT,jasonatran/RIOT,A-Paul/RIOT,kbumsik/RIOT,x3ro/RIOT,authmillenon/RIOT,BytesGalore/RIOT,kaspar030/RIOT,rfuentess/RIOT,lazytech-org/RIOT,ant9000/RIOT,lazytech-org/RIOT,x3ro/RIOT,smlng/RIOT,basilfx/RIOT,OTAkeys/RIOT,kaspar030/RIOT,authmillenon/RIOT,smlng/RIOT,x3ro/RIOT,aeneby/RIOT,mfrey/RIOT,jasonatran/RIOT,miri64/RIOT,smlng/RIOT,ant9000/RIOT,yogo1212/RIOT,lazytech-org/RIOT,josephnoir/RIOT,kaspar030/RIOT,gebart/RIOT,mtausig/RIOT,gebart/RIOT,gebart/RIOT,miri64/RIOT,rfuentess/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,jasonatran/RIOT,RIOT-OS/RIOT,rfuentess/RIOT,avmelnikoff/RIOT,cladmi/RIOT,cladmi/RIOT,yogo1212/RIOT,OTAkeys/RIOT,authmillenon/RIOT,jasonatran/RIOT,aeneby/RIOT,avmelnikoff/RIOT,toonst/RIOT,miri64/RIOT,mfrey/RIOT,mfrey/RIOT,smlng/RIOT,yogo1212/RIOT,RIOT-OS/RIOT,cladmi/RIOT,yogo1212/RIOT,mtausig/RIOT,rfuentess/RIOT,kaspar030/RIOT,avmelnikoff/RIOT,kYc0o/RIOT,kbumsik/RIOT,authmillenon/RIOT,BytesGalore/RIOT,avmelnikoff/RIOT,josephnoir/RIOT