Silence ProcessLookupError in ScopedPopen.__del__.

git-svn-id: https://svn.nmap.org/nmap-exp/d33tah/ncat-test-py@32614 e0a8ed71-7df4-0310-8962-fdc924857419
Clarify the first test's comment.

git-svn-id: https://svn.nmap.org/nmap-exp/d33tah/ncat-test-py@32615 e0a8ed71-7df4-0310-8962-fdc924857419
Add a second test.

git-svn-id: https://svn.nmap.org/nmap-exp/d33tah/ncat-test-py@32616 e0a8ed71-7df4-0310-8962-fdc924857419