Fix incorrect logging in krb5_parse_name() error handling

[Fahnenfluchtige]

The Svace static analysis tool identified a potential issue in the function ngx_http_auth_spnego_basic(), where the variable code might incorrectly store the value from krb5_init_context() instead of the return value from krb5_parse_name(), which causes incorrect error logging. In the current situation, line 922

spnego_log_krb5_error(kcontext, code);

logs the value of code, which was previously set by krb5_init_context(), instead of the expected return value from krb5_parse_name()
Moreover, krb5_parse_name() returns a value of type krb5_error_code, while kret does not match this data type and is not used elsewhere in file. Keeping the variable kret may be unnecessary. Instead, the return value of krb5_parse_name() should be directly assigned to code

To resolve this issue, kret should be removed, and code should be used to store the return value of krb5_parse_name() to ensure correct error logging:

diff --git a/ngx_http_auth_spnego_module.c b/ngx_http_auth_spnego_module.c
index 4a89065..dfdead6 100644
--- a/ngx_http_auth_spnego_module.c
+++ b/ngx_http_auth_spnego_module.c
@@ -883,7 +883,6 @@ ngx_int_t ngx_http_auth_spnego_basic(ngx_http_request_t *r,
     krb5_principal server = NULL;
     krb5_creds creds;
     krb5_get_init_creds_opt *gic_options = NULL;
-    int kret = 0;
     char *name = NULL;
     char *p = NULL;
 
@@ -915,9 +914,9 @@ ngx_int_t ngx_http_auth_spnego_basic(ngx_http_request_t *r,
                      &host_name, &alcf->realm);
     }
 
-    kret = krb5_parse_name(kcontext, (const char *)service.data, &server);
+    code = krb5_parse_name(kcontext, (const char *)service.data, &server);
 
-    if (kret) {
+    if (code) {
         spnego_log_error("Kerberos error:  Unable to parse service name");
         spnego_log_krb5_error(kcontext, code);
         spnego_error(NGX_ERROR);