Move out: label to inside #endif of HAVE_DLOPEN
Samba compiles Heimdal internally without HAVE_DLOPEN to keep
to internally supplied mechanisms and plugins.
Samba compiles with strict warning flags and on Ubuntu 20.04
with gcc version 9.3.0 (Ubuntu 9.3.0-17ubuntu1~20.04) we see:
../../source4/heimdal/lib/gssapi/mech/gss_mech_switch.c: In function ‘_gss_load_mech’:
../../source4/heimdal/lib/gssapi/mech/gss_mech_switch.c:462:1: error: label ‘out’ defined but not used [-Werror=unused-label]
462 | out:
| ^~~
cc1: all warnings being treated as errors
Signed-off-by: Andrew Bartlett <abartlet@samba.org>