Fix a few memory leaks.  send-pr:20061030

Index: src/kdc/kdc_preauth.c
===================================================================
--- src/kdc/kdc_preauth.c	(revision 18750)
+++ src/kdc/kdc_preauth.c	(working copy)
@@ -349,6 +352,7 @@
      * leave room for a terminator entry. */
     preauth_systems = malloc(sizeof(krb5_preauth_systems) * (module_count + 1));
     if (preauth_systems == NULL) {
+	krb5int_free_plugin_dir_data(preauth_plugins_ftables);
 	return ENOMEM;
     }
 
@@ -414,6 +418,7 @@
 	    }
 	}
     }
+    krb5int_free_plugin_dir_data(preauth_plugins_ftables);
     n_preauth_systems = k;
     /* Add the end-of-list marker. */
     preauth_systems[k].name = "[end]";
Index: src/lib/crypto/string_to_key.c
===================================================================
--- src/lib/crypto/string_to_key.c	(revision 18750)
+++ src/lib/crypto/string_to_key.c	(working copy)
@@ -93,6 +93,7 @@
     if (ret) {
 	memset(key->contents, 0, keylength);
 	free(key->contents);
+	key->contents = NULL;
     }
 
     return(ret);
Index: src/lib/krb5/krb/preauth2.c
===================================================================
--- src/lib/krb5/krb/preauth2.c	(revision 18750)
+++ src/lib/krb5/krb/preauth2.c	(working copy)
@@ -167,11 +167,13 @@
     /* allocate the space we need */
     context = malloc(sizeof(*context));
     if (context == NULL) {
+        krb5int_free_plugin_dir_data(tables);
         return;
     }
     context->modules = malloc(sizeof(context->modules[0]) * n_modules);
     if (context->modules == NULL) {
         free(context);
+        krb5int_free_plugin_dir_data(tables);
         return;
     }
     memset(context->modules, 0, sizeof(context->modules[0]) * n_modules);
@@ -216,6 +219,7 @@
 	}
     }
 
+    krb5int_free_plugin_dir_data(tables);
     /* return the result */
     *preauth_context = context;
 }