Fix memory leaks

[lucic71]

[lucic71]

hashstr_buf also seems to be read in a lot of places but never written.

Edit: hastype_t.final, which usee hashstr_buf, isn't written anywhere, as well.

[davidpolverari]

Hmm. For this one, I will leave it for the time when I'm able to run it through valgrind and gdb (probably over the weekend) and see whether data is ever written on those locations.

[hartwork]

@davidpolverari unfixed compile warnings in the CI logs seem to confirm. This is for latest master:

2024-05-08T02:42:50.0167219Z verify.c:147:11: warning: variable 'i_hashstr_buf' set but not used [-Wunused-but-set-variable]
2024-05-08T02:42:50.0167811Z   147 |     char *i_hashstr_buf;
2024-05-08T02:42:50.0168195Z       |           ^
2024-05-08T02:42:50.0168870Z verify.c:148:11: warning: variable 'v_hashstr_buf' set but not used [-Wunused-but-set-variable]
2024-05-08T02:42:50.0169458Z   148 |     char *v_hashstr_buf;
2024-05-08T02:42:50.0169840Z       |           ^

[davidpolverari]

Merged on master. Closing manually, as I had to rebase before merging. Thanks for the help!