utils_test: Add two functions for libvirt tests

Function to check virsh commands exit status.
Function to check interface for virsh iface related tests.

Signed-off-by: Yanbing Du <ydu@redhat.com>

Conflicts:
	virttest/utils_test/libvirt.py
virttest.virsh: Add wrappers for iface related commands

Signed-off-by: Yanbing Du <ydu@redhat.com>
Typo fix

Signed-off-by: Yanbing Du <ydu@redhat.com>
Merge pull request #1587 from will-Do/iface

Add iface related commands wrappers and libvirt common test functions
requirements.txt: Cleanups

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
tools: Remove check_patch and other auxiliary scripts

As they've been replaced by inspekt.

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
virttest.staging.backports.simplejson: Supress E0111 message

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
documentation: .rst fixes

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>
virttest: Docstring fixes

Signed-off-by: Lucas Meneghel Rodrigues <lmr@redhat.com>