KCM: another memory leak fixed

```
...
    talloc_new: src/responder/kcm/kcmsrv_ccache.c:405 contains      0 bytes in   1 blocks (ref 0) 0x563feaabc0a0
    talloc_new: src/responder/kcm/kcmsrv_ccache.c:405 contains      0 bytes in   1 blocks (ref 0) 0x563feaa84f90
    talloc_new: src/responder/kcm/kcmsrv_ccache.c:405 contains      0 bytes in   1 blocks (ref 0) 0x563feaabf520
...
```

Reviewed-by: Alejandro López <[email protected]>
(cherry picked from commit 9e72bc2)

src/responder/kcm/kcmsrv_ccache.c

@@ -407,7 +407,7 @@ krb5_creds **kcm_cc_unmarshal(TALLOC_CTX *mem_ctx,
 
     tmp_ctx = talloc_new(NULL);
     if (tmp_ctx == NULL) {
-        goto done;
+        goto fail;
     }
 
     for (cred = kcm_cc_get_cred(cc); cred != NULL; cred = kcm_cc_next_cred(cred)) {
@@ -420,7 +420,7 @@ krb5_creds **kcm_cc_unmarshal(TALLOC_CTX *mem_ctx,
         cred_list[i] = kcm_cred_to_krb5(krb_context, cred);
         if (cred_list[i] == NULL) {
             DEBUG(SSSDBG_CRIT_FAILURE, "Failed to convert kcm cred to krb5\n");
-            goto done;
+            goto fail;
         }
     }
 
@@ -429,8 +429,10 @@ krb5_creds **kcm_cc_unmarshal(TALLOC_CTX *mem_ctx,
 
     talloc_steal(mem_ctx, cred_list);
 
+    talloc_free(tmp_ctx);
     return cred_list;
-done:
+
+fail:
     talloc_free(tmp_ctx);
     return NULL;
 #endif