'ip -oneline tunnel show' was not "oneline" for GRE tunnels with iseq:
# ip tun add gre_test remote 1.1.1.1 local 2.2.2.2 mode gre iseq oseq
# ip -oneline tun show gre_test | wc -l
2

The problem existed because of a typo: '\n' was printed when it shouldn't be.
Fixed.
Signed-off-by: Dmitry Popov <ixaphire@qrator.net>