Mock calls to rpm and dpkg from NetApp unit tests

This patch fixes an issue wherein several NetApp unit tests ran
OS rpm or dpkg commands because the callouts to these commands
were not mocked out during driver initialization.

It also replaces 'rpm -qa' with 'rpm -q' when that command is
invoked since the latter also works and is faster.

Closes-Bug: 1393545
Change-Id: I3d5cfeb2ee39ecb6af5b312dfa6c2a585cf8e0e3
Merge "Mock calls to rpm and dpkg from NetApp unit tests"