whpx nvmm: Drop useless migrate_del_blocker()

There is nothing to delete after migrate_add_blocker() failed.  Trying
anyway is safe, but useless.  Don't.

Cc: Sunil Muthuswamy <[email protected]>
Cc: Kamil Rytarowski <[email protected]>
Cc: Reinoud Zandijk <[email protected]>
Signed-off-by: Markus Armbruster <[email protected]>
Message-Id: <[email protected]>
Reviewed-by: Reinoud Zandijk <[email protected]>
Acked-by: Michael S. Tsirkin <[email protected]>

Author: Markus Armbruster

target/i386/nvmm/nvmm-all.c

@@ -929,7 +929,6 @@ nvmm_init_vcpu(CPUState *cpu)
         (void)migrate_add_blocker(nvmm_migration_blocker, &local_error);
         if (local_error) {
             error_report_err(local_error);
-            migrate_del_blocker(nvmm_migration_blocker);
             error_free(nvmm_migration_blocker);
             return -EINVAL;
         }

target/i386/whpx/whpx-all.c

@@ -1349,7 +1349,6 @@ int whpx_init_vcpu(CPUState *cpu)
         (void)migrate_add_blocker(whpx_migration_blocker, &local_error);
         if (local_error) {
             error_report_err(local_error);
-            migrate_del_blocker(whpx_migration_blocker);
             error_free(whpx_migration_blocker);
             ret = -EINVAL;
             goto error;