bitbake: parse/ConfHandler: Add negative lookahead to spot some quoting problems

bitbake: parse/ConfHandler: Add negative lookahead to spot some quoting problems

Syntax like:

FOO = "bar" # eek"

would result in FOO taking the value 'bar" #eek' which is clearly
not the intention. Whilst our metadata is riddled with mixtures of even
quotes like:

FOO = "d.getVar("X")"

odd numbers of quotes seem rare. This patch adds detection of one odd
quote which we don't have any of in OE-Core so it seems a valid sanity
improvement.

(Bitbake rev: 5f892d9b083550e20e37576070ec7d1a94cc88fe)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>