Isolate avocado.sysinfo from being used by test developers.

Move avocado.sysinfo to avocado.core.sysinfo, in conformance to our
purpose of keeping things not related to test developers, inside
avocado.core, isolated from users.
Signed-off-by: NRudá Moura <rmoura@redhat.com>

avocado/core/job.py

@@ -29,7 +29,9 @@ import fnmatch
 from avocado import multiplexer
 from avocado import result
 from avocado import runtime
-from avocado import sysinfo
+from avocado.core import runner
+from avocado.core import loader
+from avocado.core import sysinfo
 from avocado.core import runner
 from avocado.core import loader
 from avocado.core import data_dir

avocado/plugins/sysinfo.py

@@ -16,7 +16,7 @@ System information plugin
 """
 
 from avocado.plugins import plugin
-from avocado import sysinfo
+from avocado.core import sysinfo
 
 
 class SystemInformation(plugin.Plugin):

avocado/test.py

@@ -31,7 +31,8 @@ if sys.version_info[:2] == (2, 6):
 else:
     import unittest
 
-from avocado import sysinfo, multiplexer
+from avocado import multiplexer
+from avocado.core import sysinfo
 from avocado.core import data_dir
 from avocado.core import exceptions
 from avocado.utils import genio

selftests/all/unit/avocado/sysinfo_unittest.py

@@ -14,7 +14,7 @@ basedir = os.path.dirname(basedir)
 if os.path.isdir(os.path.join(basedir, 'avocado')):
     sys.path.append(basedir)
 
-from avocado import sysinfo
+from avocado.core import sysinfo
 
 
 class SysinfoTest(unittest.TestCase):