Check indents on comment lines

The check makes sense for comment lines as well.

An example:

    if :; then
    <tab># comment
    <spaces>echo hello
    fi

Change-Id: I3baff60fe272440bbcbe5dd809f264bca1092b78

bashate/bashate.py

@@ -334,6 +334,8 @@ class BashateRun(object):
                 # inside a heredoc this might be part of the syntax of
                 # an embedded script, just ignore that)
                 if line.lstrip().startswith('#') and not in_heredoc:
+                    logical_line = [line]
+                    check_indents(logical_line, report)
                     continue
 
                 # Strip trailing comments. From bash:

bashate/tests/samples/comments.sh

@@ -21,6 +21,10 @@ fi
 
 # ``RST style comment``
 
- # ``indented comment``
+ # ``indented comment`` (E003)
+
+    # ``indented comment`` (4 spaces, ok)
+
+	# ``indented comment`` (tab, E002)
 
 #	tab comment

bashate/tests/test_bashate.py

@@ -260,7 +260,10 @@ class TestBashateSamples(base.TestCase):
         test_files = ['bashate/tests/samples/comments.sh']
         self.run.check_files(test_files, False)
 
-        self.assertEqual(0, self.run.error_count)
+        self.assert_error_found('E003', 24)
+        self.assert_error_found('E002', 28)
+        self.assert_error_found('E003', 28)
+        self.assertEqual(3, self.run.error_count)
 
     def test_sample_E005(self):
         test_files = ['bashate/tests/samples/E005_bad']