Fix indentation of the error message should Ruby of libmagic be missing.
Fix indentation of the error message should Ruby of libmagic be missing.

Signed-off-by: Krzysztof Wilczynski <5f1c0be89013f8fde969a8dcb2fa1d522e94ee00@linux.com>

kwilczynski/ruby-magic,kwilczynski/ruby-magic