Fix task_manager acquire post landing for c4f2f26ed

In original implementation we used context lib with try/finally
to make sure release_resources will be called even if there was an
exception inside acquire_resources. With c4f2f26ed we broke that
functionality, so this patch intended to fix this.

Closes-Bug: #1279992
Change-Id: I04abc67aedc226bc126b1d93901c71bcd8a5bf15