examples: Some shell fixes to cbq.init

examples: Some shell fixes to cbq.init

This addresses the following issues:

- $@ is an array, so don't use it in quoted strings - use $* instead.

- Add missing quotes to components of [ ] expressions. These are not
  strictly necessary since the output of 'wc -l' should be a single word
  only, but in case of errors, bash prints "integer expression expected"
  instead of "too many arguments".

- Use -print0/-0 when piping from find to xargs to allow for filenames
  which contain whitespace.

- Quote arguments to 'eval' to prevent word-splitting.

Signed-off-by: Phil Sutter <phil@nwl.cc>