core: sync SeccompParseFlags between dbus-execute and load-fragment

9e48626 added some new syscalls to the
filter lists. However, on systems that do not yet support the new calls,
running systemd-run with the filter set results in error:

```
$ sudo systemd-run -t -r -p "SystemCallFilter=~@mount" /bin/true
Failed to start transient service unit: Invalid argument
```

Having the same properties in a unit file will start the service
without issue. This is because the load-fragment code will parse the
syscall filters in permissive mode:
https://github.com/systemd/systemd/blob/master/src/core/load-fragment.c#L2909
whereas the dbus-execute equivalent of the code does not.

Since the permissive mode appears to be the right setting to support
older kernels/libseccomp, this will update the dbus-execute parsing
to also be permissive.

Author: anitazha

src/core/dbus-execute.c

@@ -1587,6 +1587,7 @@ int bus_exec_context_set_transient_property(
                                         r = seccomp_parse_syscall_filter("@default",
                                                                          -1,
                                                                          c->syscall_filter,
+                                                                         SECCOMP_PARSE_PERMISSIVE |
                                                                          SECCOMP_PARSE_WHITELIST | invert_flag,
                                                                          u->id,
                                                                          NULL, 0);
@@ -1606,7 +1607,9 @@ int bus_exec_context_set_transient_property(
                                 r = seccomp_parse_syscall_filter(n,
                                                                  e,
                                                                  c->syscall_filter,
-                                                                 (c->syscall_whitelist ? SECCOMP_PARSE_WHITELIST : 0) | invert_flag,
+                                                                 SECCOMP_PARSE_LOG | SECCOMP_PARSE_PERMISSIVE |
+                                                                 invert_flag |
+                                                                 (c->syscall_whitelist ? SECCOMP_PARSE_WHITELIST : 0),
                                                                  u->id,
                                                                  NULL, 0);
                                 if (r < 0)