contribs: fix error handling while compressing tar archives
When the shell evaluates 'foo | bar', it returns the status of bar, not foo. 'foo' can fail silently: so long as 'bar' succeeds, make will not notice and will therefore not delete the target. So lets use 'tar cv(z|j|J)' instead of 'tar cv | (gzip|bzip2|xz)'.
Showing with 2 additions and 2 deletions