Revert "scanner: flags: move to own scope"

Revert "scanner: flags: move to own scope"

Excess nesting of scanner scopes is very fragile and error prone:

rule `iif != lo ip daddr 127.0.0.1/8 counter limit rate 1/second log flags all prefix "nft_lo4 " drop`
fails with `Error: No symbol type information` hinting at `prefix`

Problem is that we nest via:
 counter
   limit
     log
    flags

By the time 'prefix' is scanned, state is still stuck in 'counter' due
to this nesting.  Working around "prefix" isn't enough, any other
keyword, e.g. "level" in 'flags all level debug' will be parsed as 'string' too.

So, revert this.

Fixes: a16697097e2b ("scanner: flags: move to own scope")
Reported-by: Christian Göttsche <cgzones@googlemail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>