Fix loadmaster privesc check method and refs

[h00die]

linux/local/progress_kemp_loadmaster_sudo_privesc_2024 has 2 issues when running on a non-loadmaster device:

1. CVE in URL isn't listed as CVE in references
2. check method crashes if the files don't exist.
3. While in there, also moved the prints into the returned check code

Pre

[msf](Jobs:2 Agents:1) exploit(linux/local/progress_kemp_loadmaster_sudo_privesc_2024) > recheck
[*] Reloading module...
[-] Failed to open file: /usr/wui/index.js: core_channel_open: Operation failed: 1
[-] Exploit failed: NoMethodError undefined method `include?' for nil:NilClass
[-] Check failed: The state could not be determined.

Post

[msf](Jobs:2 Agents:1) exploit(linux/local/progress_kemp_loadmaster_sudo_privesc_2024) > recheck
[*] Reloading module...
[*] The target is not exploitable. Found 0 indicators this is a KEMP product