bash_completion: don't complete export with "garbage" when mq is not around
The "garbage" is the output of hg help printed when a command is not found.
#!/bin/shmkdir acd ahg initecho foo > bhg add bhg ci -m "b" -d "1000000 0"chmod -w .hgcd ..hg clone a bchmod +w a/.hg # let test clean upcd bhg verify