rbld run: Support execution with non-tty stdin
rbld run: Support execution with non-tty stdin

This patch fixes error:

  cannot enable tty mode on non tty input

when running rbld run with piped/redirected stdin

Signed-off-by: Dmitry Fleytman <a8cf97adadec4e1b734a39bc5aea71b5741cfca1@daynix.com>

rbld/rebuild,rbld/rebuild,daynix/rebuild,daynix/rebuild,rbld/rebuild,daynix/rebuild