envsetup: fix for provision to work on zsh

The -p option means something else on zsh and breaks this function.

Bug: None
Change-Id: Ie0ba8119e34c616f5b8f931806063d6b1d3d893e
diff --git a/envsetup.sh b/envsetup.sh
index c3e467c..45f70b3 100644
--- a/envsetup.sh
+++ b/envsetup.sh
@@ -1520,7 +1520,8 @@
         echo ""
         echo "ALL DATA ON THE DEVICE WILL BE IRREVOCABLY ERASED."
         echo ""
-        read -p "Are you sure you want to do this (yes/no)? "
+        echo -n "Are you sure you want to do this (yes/no)? "
+        read
         if [[ "${REPLY}" != "yes" ]] ; then
             echo "Not taking any action. Exiting." >&2
             return 1