src/context: don't warn about trailing new line in variant file
src/context: don't warn about trailing new line in variant file

Since 60fc2722a820 ("src/context: remove surrounding whitespace from
system variant"), RAUC will warn when it strips away the whitespace.

It's customary however for UNIX files to have a trailing new line,
so skip the warning if that's the only trailing whitespace.

Signed-off-by: Ahmad Fatoum <80b35bd4ec794be50741ee03ee9012283f27989b@pengutronix.de>

ejoerns/rauc,rauc/rauc,ejoerns/rauc,jluebbe/rauc,jluebbe/rauc,rauc/rauc,jluebbe/rauc,ejoerns/rauc,rauc/rauc