oeqa/runtime/utils/targetbuildproject: Use a subdir within ~/

Without doing this, the code can and sometimes does try and do "rm ~/"
which I think we'd all prefer it didn't.

(From OE-Core rev: 9dc1de59330c366783ea043c68c1b59b1b49e707)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/runtime/utils/targetbuildproject.py

@@ -7,10 +7,12 @@ class TargetBuildProject(BuildProject):
 
     def __init__(self, target, uri, foldername=None, dl_dir=None):
         self.target = target
-        self.targetdir = "~/"
+        self.targetdir = "~/buildtest/"
         BuildProject.__init__(self, uri, foldername, dl_dir=dl_dir)
 
     def download_archive(self):
+        self.target.run("mkdir " + self.targetdir + " || true")
+
         self._download_archive()
 
         status, output = self.target.copyTo(self.localarchive, self.targetdir)