[krbdev.mit.edu #8357] memleak in gssint_get_mechanism()

[Will Fiveash via RT]

In gssint_get_mechanism() there is:

	if (krb5int_open_plugin(aMech->uLibName, &dl, &errinfo) != 0 ||
	    errinfo.code != 0) {
#if 0
		(void) syslog(LOG_INFO, "libgss dlopen(%s): %s\n",
				aMech->uLibName, dlerror());
#endif
		k5_mutex_unlock(&g_mechListLock);
		return ((gss_mechanism)NULL);
	}

I think k5_clear_error(&errinfo) should be called before the return here
to avoid leaking memory allocated to errinfo.  Here is the allocation
stack that leaks:

Found 4 leaked blocks with total size 334 bytes
At time of each allocation, the call stack was:
        [1] vasprintf() at 0x7ff03ae9f130
        [2] k5_vset_error() at line 56 in "errors.c"
        [3] k5_set_error() at line 44 in "errors.c"
        [4] krb5int_open_plugin() at line 187 in "plugins.c"
        [5] gssint_get_mechanism() at line 1257 in "g_initialize.c"
        [6] gss_add_cred_from() at line 383 in "g_acquire_cred.c"
        [7] gss_acquire_cred_from() at line 186 in "g_acquire_cred.c"
        [8] get_available_mechs() at line 3233 in "spnego_mech.c"