test/py: Quote consistency

When converting test/py from " to ', I missed a few places (or added a
few inconsistencies later). Fix these.

Note that only quotes in code are converted; double-quotes in comments
and HTML are left as-is, since English and HTML use " not '.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/test_dfu.py b/test/py/tests/test_dfu.py
index 0f69eef..c09b902 100644
--- a/test/py/tests/test_dfu.py
+++ b/test/py/tests/test_dfu.py
@@ -258,7 +258,7 @@
         dfu_write(0, dummy_f.abs_fn)
 
         for size in sizes:
-            with u_boot_console.log.section("Data size %d" % size):
+            with u_boot_console.log.section('Data size %d' % size):
                 dfu_write_read_check(size)
                 # Make the status of each sub-test obvious. If the test didn't
                 # pass, an exception was thrown so this code isn't executed.
diff --git a/test/py/tests/test_net.py b/test/py/tests/test_net.py
index 68eedde..07393eb 100644
--- a/test/py/tests/test_net.py
+++ b/test/py/tests/test_net.py
@@ -112,7 +112,7 @@
     """
 
     if not net_set_up:
-        pytest.skip("Network not initialized")
+        pytest.skip('Network not initialized')
 
     output = u_boot_console.run_command('ping $serverip')
     assert 'is alive' in output
@@ -129,7 +129,7 @@
     """
 
     if not net_set_up:
-        pytest.skip("Network not initialized")
+        pytest.skip('Network not initialized')
 
     f = u_boot_console.config.env.get('env__net_tftp_readable_file', None)
     if not f:
diff --git a/test/py/tests/test_shell_basics.py b/test/py/tests/test_shell_basics.py
index 32e5f83..702e5e2 100644
--- a/test/py/tests/test_shell_basics.py
+++ b/test/py/tests/test_shell_basics.py
@@ -31,7 +31,7 @@
 def test_shell_run(u_boot_console):
     """Test the "run" shell command."""
 
-    u_boot_console.run_command('setenv foo \"setenv monty 1; setenv python 2\"')
+    u_boot_console.run_command('setenv foo "setenv monty 1; setenv python 2"')
     u_boot_console.run_command('run foo')
     response = u_boot_console.run_command('echo $monty')
     assert response.strip() == '1'