[Fix] `nvm_iojs_version_has_solaris_binary`: fix comparison to detect non-iojs versions

Missing `_` prefix on the right side of the comparison meant the guard clause that rejects non-iojs versions almost never matched, allowing non-iojs versions to fall through.

Bug introduced in https://github.com/nvm-sh/nvm/commit/2d692d9d7863844d9e5c499faf423b350235f72d / #854.