Fix install_reclass conflict --targe/--preffix options

Change-Id: I5a3958857341f2ba2352cce3d8b0ff6244207161
diff --git a/bootstrap.sh b/bootstrap.sh
index b35b879..f9372a3 100755
--- a/bootstrap.sh
+++ b/bootstrap.sh
@@ -387,7 +387,7 @@
         # For dev/git/pip version...
         # Note: It replaces all local reclass versions on system
         for s in $(python -c "import site; print(' '.join(site.getsitepackages()))"); do
-          sudo -H pip install --upgrade --force-reinstall -I \
+          sudo -H pip install --install-option="--prefix=" --upgrade --force-reinstall -I \
             -t "$s" git+https://github.com/salt-formulas/reclass.git@${VERSION};
         done
         ;;