poco: Remove pushd/popd from run-ptest

This could be worked out without needing to add bash dependency

Signed-off-by: Khem Raj <raj.khem@gmail.com>
Signed-off-by: Peter Marko <peter.marko@siemens.com>
Signed-off-by: Armin Kuster <akuster808@gmail.com>

meta-oe/recipes-support/poco/poco/run-ptest

@@ -1,9 +1,8 @@
 #!/bin/sh
 while read runner; do
-  pushd . >/dev/null
+  oldpath=`pwd` >/dev/null
   cd bin
   echo Testing $runner
   ./$runner-testrunner -all
-  popd >/dev/null
+  cd $oldpath >/dev/null
 done < testrunners
-