bash completion fails if user has a "grep" alias that produces unexpected output formatting

[smu-ggl]

Example:
alias grep="grep -P"

This could be avoided by using absolute paths for grep (and possibly other commands) or by protecting the relevant parts of the completion with "shopt -u expand_aliases" while executing the expansions.

I haven't done too much research yet, but this probably mostly affects
bazel-complete-template.bash lines 229 320 360 405 but probably not 190.

I'd suggest to just replace all occurrences of "grep" with /bin/grep (and probably do the same for sed)

[damienmg]

This was done 86a4047