Mutliline values for traceback or stdout/stderr are not properly indented

[memoselyk]

I have observed this issue with junit-xml==1.8 and Jenkins 2.46.3.
In case it matters I'm using xUnit plugin to publish Junit results.

Steps to reproduce

Create a test case with a multi-line output or traceback, e.g.

stdout = "line1\nline2"
traceback = "line1\nline2"
tc = TestCase(name=name, classname=classname, stdout=stdout)
tc.add_error_info(output=traceback)

Expected behavior

In the test case details displayed in Jenkins the multi-line values are shown like

line1
line2

Based on the formatting of test cases in the xunit plugin, I assume the proper tag to be generated should be:

			<system-out>
				line1
                                line2
			</system-out>

Actual behavior

The first line has an extra indentation:

            line1
line2

That is caused by the indentation given to text of the relevant tag:

			<system-out>
				line1
line2
			</system-out>

[brianebeyer]

Thanks @memoselyk - please submit a PR with tests if you'd like this behavior to change