pkg/tar: enhance error message in ExtractTarInsecure()
pkg/tar: enhance error message in ExtractTarInsecure()

Sometimes tests fail on `ExtractTarInsecure()` and the error message was not clear
enough to reproduce the fail. In case of error from `extractFile()` or `UtimesNano()`,
`ExtractTarInsecure()` adds the file name to the returned error.

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