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/shhg initecho This is file a1 > ahg add ahg commit -m "commit #0" -d "1000000 0"touch bhg add brm bhg commit -A -m"comment #1" -d "1000000 0"