fix(dracut-install): release memory allocated for regular expressions

[aafeijoo-suse]

Use regfree to free memory allocated by regcomp. Quoting [1]:

"If the preg argument to regexec() or regfree() is not a compiled regular expression returned by regcomp(), the result is undefined."

Therefore, regfree must only be called if regcomp succeeded.

[1] https://pubs.opengroup.org/onlinepubs/9699919799/functions/regcomp.html

Checklist

• [X] I have tested it locally
• [ ] I have reviewed and updated any documentation if relevant
• [ ] I am providing new code and test(s) for it

[stale[bot]]

This issue is being marked as stale because it has not had any recent activity. It will be closed if no further activity occurs. If this is still an issue in the latest release of Dracut and you would like to keep it open please comment on this issue within the next 7 days. Thank you for your contributions.

[stale[bot]]

This issue is being marked as stale because it has not had any recent activity. It will be closed if no further activity occurs. If this is still an issue in the latest release of Dracut and you would like to keep it open please comment on this issue within the next 7 days. Thank you for your contributions.