functional tests: fix skipping tests on remote fetch failure
functional tests: fix skipping tests on remote fetch failure

If we call `t.Errorf` before skipping, our test will fail...

akshaykarle/rkt,jakon89/rkt,tmrts/rkt,achanda/rkt,nhlfr/rkt,nhlfr/rkt,dgonyeo/rkt,coreos/rkt,jonboulle/rkt,joshix/rkt,euank/rkt,dgonyeo/rkt,coreos/rkt,euank/rkt,tmrts/rkt,akshaykarle/rkt,euank/rkt,joshix/rkt,monstermunchkin/rkt,alban/rkt,yifan-gu/rkt,jjlakis/rkt,Shashwatsh/rkt,cab105/rkt,lucasallan/rkt,ybubnov/rkt,shobhit85/rkt,cab105/rkt,intelsdi-x/rkt,jjlakis/rkt,yifan-gu/rocket,Shashwatsh/rkt,alban/rkt,yifan-gu/rkt,rkt/rkt,achanda/rkt,cab105/rkt,s-urbaniak/rkt,shobhit85/rkt,monstermunchkin/rkt,achanda/rkt,nhlfr/rkt,kinvolk/rkt,rkt/rkt,sgotti/rkt,s-urbaniak/rkt,akshaykarle/rkt,squeed/rkt,lucasallan/rkt,joshix/rkt,monstermunchkin/rkt,kinvolk/rkt,Wilybald/rkt,squeed/rkt,dgonyeo/rkt,yifan-gu/rocket,rkt/rkt,Shashwatsh/rkt,sstabellini/rkt,intelsdi-x/rkt,jakon89/rkt,jjlakis/rkt,squeed/rkt,yifan-gu/rocket,s-urbaniak/rkt,kinvolk/rkt,Wilybald/rkt,joshix/rkt,Wilybald/rkt,kinvolk/rkt,sgotti/rkt,jonboulle/rkt,jonboulle/rkt,sstabellini/rkt,lucasallan/rkt,alban/rkt,sgotti/rkt,intelsdi-x/rkt,ybubnov/rkt,tmrts/rkt,rkt/rkt,Wilybald/rkt,lucasallan/rkt,yifan-gu/rkt,jakon89/rkt,coreos/rkt,ybubnov/rkt,sstabellini/rkt,shobhit85/rkt