pam_systemd: fix OSC write failure message appearing in error logs

Create and use new function pam_debug_syslog_errno() instead to ensure the
message only appears when debug mode is enabled. Pass the debug flag to
open_osc_context() and close_osc_context() to support this change.

src/shared/pam-util.h

@@ -35,13 +35,20 @@ int pam_syslog_errno(pam_handle_t *handle, int level, int error, const char *for
 
 int pam_syslog_pam_error(pam_handle_t *handle, int level, int error, const char *format, ...) _printf_(4,5);
 
-/* Call pam_vsyslog if debug is enabled */
+/* Call sym_pam_syslog if debug is enabled */
 #define pam_debug_syslog(handle, debug, fmt, ...)                       \
         ({                                                              \
                 if (debug)                                              \
                         sym_pam_syslog(handle, LOG_DEBUG, fmt, ## __VA_ARGS__); \
         })
 
+/* Call pam_syslog_errno if debug is enabled */
+#define pam_debug_syslog_errno(handle, debug, error, fmt, ...)          \
+        ({                                                              \
+                if (debug)                                              \
+                        pam_syslog_errno(handle, LOG_DEBUG, error, fmt, ## __VA_ARGS__); \
+        })
+
 static inline int pam_log_oom(pam_handle_t *handle) {
         /* This is like log_oom(), but uses PAM logging */
         return pam_syslog_errno(handle, LOG_ERR, ENOMEM, "Out of memory.");