unittests: Add missing check for result of vfs_opendir in tests-spiffs
unittests: Add missing check for result of vfs_opendir in tests-spiffs

A-Paul/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,beurdouche/RIOT,ant9000/RIOT,adjih/RIOT,BytesGalore/RIOT,jasonatran/RIOT,gebart/RIOT,lazytech-org/RIOT,ant9000/RIOT,plushvoxel/RIOT,LudwigOrtmann/RIOT,OTAkeys/RIOT,jasonatran/RIOT,x3ro/RIOT,cladmi/RIOT,adrianghc/RIOT,jfischer-phytec-iot/RIOT,Josar/RIOT,x3ro/RIOT,dailab/RIOT,rfuentess/RIOT,immesys/RiSyn,mtausig/RIOT,x3ro/RIOT,Hyungsin/RIOT-OS,smlng/RIOT,syin2/RIOT,yogo1212/RIOT,authmillenon/RIOT,aeneby/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,aeneby/RIOT,A-Paul/RIOT,biboc/RIOT,kaleb-himes/RIOT,kaleb-himes/RIOT,josephnoir/RIOT,neumodisch/RIOT,jasonatran/RIOT,syin2/RIOT,toonst/RIOT,BytesGalore/RIOT,kerneltask/RIOT,neumodisch/RIOT,smlng/RIOT,Ell-i/RIOT,thomaseichinger/RIOT,OlegHahm/RIOT,RIOT-OS/RIOT,syin2/RIOT,gautric/RIOT,kaleb-himes/RIOT,josephnoir/RIOT,roberthartung/RIOT,mtausig/RIOT,hamilton-mote/RIOT-OS,biboc/RIOT,dailab/RIOT,basilfx/RIOT,ant9000/RIOT,immesys/RiSyn,BytesGalore/RIOT,basilfx/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,TobiasFredersdorf/RIOT,hamilton-mote/RIOT-OS,josephnoir/RIOT,authmillenon/RIOT,lazytech-org/RIOT,kYc0o/RIOT,roberthartung/RIOT,kYc0o/RIOT,authmillenon/RIOT,avmelnikoff/RIOT,neiljay/RIOT,jfischer-phytec-iot/RIOT,Josar/RIOT,lazytech-org/RIOT,A-Paul/RIOT,RIOT-OS/RIOT,RIOT-OS/RIOT,kYc0o/RIOT,gautric/RIOT,yogo1212/RIOT,beurdouche/RIOT,kbumsik/RIOT,authmillenon/RIOT,A-Paul/RIOT,dailab/RIOT,kaspar030/RIOT,Ell-i/RIOT,kaspar030/RIOT,neumodisch/RIOT,Ell-i/RIOT,hamilton-mote/RIOT-OS,dkm/RIOT,kerneltask/RIOT,LudwigOrtmann/RIOT,LudwigKnuepfer/RIOT,neumodisch/RIOT,OlegHahm/RIOT,adrianghc/RIOT,toonst/RIOT,avmelnikoff/RIOT,Josar/RIOT,ant9000/RIOT,dkm/RIOT,adrianghc/RIOT,ks156/RIOT,BytesGalore/RIOT,gautric/RIOT,Ell-i/RIOT,biboc/RIOT,syin2/RIOT,josephnoir/RIOT,plushvoxel/RIOT,kbumsik/RIOT,hamilton-mote/RIOT-OS,smlng/RIOT,plushvoxel/RIOT,mfrey/RIOT,authmillenon/RIOT,dailab/RIOT,kbumsik/RIOT,Ell-i/RIOT,RIOT-OS/RIOT,immesys/RiSyn,aeneby/RIOT,cladmi/RIOT,mtausig/RIOT,LudwigKnuepfer/RIOT,gebart/RIOT,dailab/RIOT,cladmi/RIOT,kerneltask/RIOT,authmillenon/RIOT,OTAkeys/RIOT,thomaseichinger/RIOT,thomaseichinger/RIOT,RIOT-OS/RIOT,adrianghc/RIOT,miri64/RIOT,BytesGalore/RIOT,toonst/RIOT,TobiasFredersdorf/RIOT,jasonatran/RIOT,jfischer-phytec-iot/RIOT,roberthartung/RIOT,LudwigKnuepfer/RIOT,Josar/RIOT,gebart/RIOT,TobiasFredersdorf/RIOT,kaleb-himes/RIOT,kerneltask/RIOT,kbumsik/RIOT,LudwigOrtmann/RIOT,thomaseichinger/RIOT,neiljay/RIOT,jfischer-phytec-iot/RIOT,OlegHahm/RIOT,biboc/RIOT,plushvoxel/RIOT,ks156/RIOT,rfuentess/RIOT,x3ro/RIOT,OlegHahm/RIOT,rfuentess/RIOT,beurdouche/RIOT,TobiasFredersdorf/RIOT,LudwigOrtmann/RIOT,yogo1212/RIOT,adjih/RIOT,gebart/RIOT,kaspar030/RIOT,ant9000/RIOT,A-Paul/RIOT,kerneltask/RIOT,kaleb-himes/RIOT,beurdouche/RIOT,LudwigOrtmann/RIOT,kYc0o/RIOT,rfuentess/RIOT,josephnoir/RIOT,miri64/RIOT,roberthartung/RIOT,miri64/RIOT,mtausig/RIOT,ks156/RIOT,beurdouche/RIOT,LudwigKnuepfer/RIOT,thomaseichinger/RIOT,OlegHahm/RIOT,basilfx/RIOT,basilfx/RIOT,roberthartung/RIOT,TobiasFredersdorf/RIOT,smlng/RIOT,dkm/RIOT,ks156/RIOT,immesys/RiSyn,yogo1212/RIOT,Josar/RIOT,Hyungsin/RIOT-OS,adjih/RIOT,immesys/RiSyn,neiljay/RIOT,aeneby/RIOT,jasonatran/RIOT,hamilton-mote/RIOT-OS,Hyungsin/RIOT-OS,OTAkeys/RIOT,x3ro/RIOT,biboc/RIOT,toonst/RIOT,cladmi/RIOT,avmelnikoff/RIOT,LudwigKnuepfer/RIOT,Hyungsin/RIOT-OS,neumodisch/RIOT,gautric/RIOT,avmelnikoff/RIOT,kaspar030/RIOT,dkm/RIOT,adrianghc/RIOT,lazytech-org/RIOT,jfischer-phytec-iot/RIOT,cladmi/RIOT,immesys/RiSyn,avmelnikoff/RIOT,Hyungsin/RIOT-OS,adjih/RIOT,neiljay/RIOT,yogo1212/RIOT,syin2/RIOT,dkm/RIOT,OTAkeys/RIOT,mfrey/RIOT,gebart/RIOT,kYc0o/RIOT,mtausig/RIOT,neiljay/RIOT,mfrey/RIOT,mfrey/RIOT,yogo1212/RIOT,rfuentess/RIOT,smlng/RIOT,miri64/RIOT,mfrey/RIOT,OTAkeys/RIOT,ks156/RIOT,plushvoxel/RIOT,kaspar030/RIOT,gautric/RIOT,basilfx/RIOT,aeneby/RIOT,LudwigOrtmann/RIOT,toonst/RIOT,neumodisch/RIOT,lazytech-org/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,foss-for-synopsys-dwc-arc-processors/RIOT,kbumsik/RIOT,miri64/RIOT,adjih/RIOT