devtool: do not leave behind source trees in workspace/sources

These are typically auto-extracted with modify/upgrade from recipes
and can be easily recreated. On the rare occasions where they need
to be reused, they are still available under workspace/attic (which
is already used for old recipes and appends), so nothing gets lost.

This avoids the annoyance of devtool refusing to proceed because
there is a previous source tree in workspace/sources.

For independent source trees behave as before: do nothing.

Adjust the test that previously deleted those trees by hand.

(From OE-Core rev: 9bfb95d070d68d5ab5adfe0ea096f5fbf9cad8b0)

Signed-off-by: Alexander Kanavin <alex@linutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/selftest/cases/devtool.py

@@ -1957,7 +1957,6 @@ class DevtoolUpgradeTests(DevtoolBase):
         self._test_recipe_contents(newrecipefile, checkvars, [])
         # Try again - change just name this time
         result = runCmd('devtool reset -n %s' % newrecipename)
-        shutil.rmtree(newsrctree)
         add_recipe()
         newrecipefile = os.path.join(self.workspacedir, 'recipes', newrecipename, '%s_%s.bb' % (newrecipename, recipever))
         result = runCmd('devtool rename %s %s' % (recipename, newrecipename))
@@ -1970,7 +1969,6 @@ class DevtoolUpgradeTests(DevtoolBase):
         self._test_recipe_contents(newrecipefile, checkvars, [])
         # Try again - change just version this time
         result = runCmd('devtool reset -n %s' % newrecipename)
-        shutil.rmtree(newsrctree)
         add_recipe()
         newrecipefile = os.path.join(self.workspacedir, 'recipes', recipename, '%s_%s.bb' % (recipename, newrecipever))
         result = runCmd('devtool rename %s -V %s' % (recipename, newrecipever))