fix and non-silent fail dpkg-overwrite error test

Commit cbcdd3ee9d86379d1b3a44e41ae8b17dc23111d0 removes the space at the
end of the debfile name dpkg send to us and we previously had included
in the pmerror message we printed on the statusfd.

Git-Dch: Ignore

test/integration/test-apt-progress-fd-error

@@ -18,5 +18,10 @@ setupaptarchive
 exec 3> apt-progress.log
 testfailure aptget install foo1 foo2 -y -o APT::Status-Fd=3
 msgtest "Ensure correct error message"
-grep -q "aptarchive/pool/foo2_0.8.15_amd64.deb :40:trying to overwrite '/usr/bin/file-conflict', which is also in package foo1 0.8.15" apt-progress.log && msgpass || (cat apt-progress.log && msgfail)
+if grep -q "aptarchive/pool/foo2_0.8.15_amd64.deb:40:trying to overwrite '/usr/bin/file-conflict', which is also in package foo1 0.8.15" apt-progress.log; then
+	msgpass
+else
+	cat apt-progress.log
+	msgfail
+fi