oe-init-build-env: Make it use the correct $OEROOT with zsh

(From OE-Core rev: f0aa69296f4c1d4214f9dbea236b0ed330b8154b)

Signed-off-by: Peter Kjellerstedt <pkj@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

oe-init-build-env

@@ -30,6 +30,8 @@ if [ -z "$ZSH_NAME" ] && [ "x$0" = "x./oe-init-build-env" ]; then
 else
    if [ -n "$BASH_SOURCE" ]; then
       OEROOT="`dirname $BASH_SOURCE`"
+   elif [ -n "$ZSH_NAME" ]; then
+      OEROOT="`dirname $0`"
    else
       OEROOT="`pwd`"
    fi