Move tests in keystoneclient

This is the suggested location for tests and is adopted by most
projects. As part of this change relative imports to package imports.

Fix all the test running and coverage code to point to the new location.

Change-Id: I01264aed14f396ab9a7242e3e72b71e1bc332675

.coveragerc

@@ -1,7 +1,7 @@
 [run]
 branch = True
 source = keystoneclient
-omit = keystoneclient/openstack/*
+omit = keystoneclient/tests/*,keystoneclient/openstack/*
 
 [report]
 ignore-errors = True

.testr.conf

@@ -1,4 +1,4 @@
 [DEFAULT]
-test_command=${PYTHON:-python} -m subunit.run discover -t ./ ./tests $LISTOPT $IDOPTION
+test_command=${PYTHON:-python} -m subunit.run discover -t ./ ./keystoneclient/tests $LISTOPT $IDOPTION
 test_id_option=--load-list $IDFILE
 test_list_option=--list