Use the installed swift scripts

This commit switches how scripts we use to launch the installed version
in the path. Previously the scripts were manually executed in the source
repo, but this has issues if you're trying to run with py3 in a system
where python == py2. Setuptools already does the shebang magic for us
at install time, so we just need to use the installed version of the
script.

Change-Id: Iaa4d80ec607a2aa200400330e16cad3a4ca782ac

Author: mtreinish

lib/swift

@@ -809,10 +809,10 @@ function start_swift {
         local proxy_port=${SWIFT_DEFAULT_BIND_PORT}
         start_tls_proxy swift '*' $proxy_port $SERVICE_HOST $SWIFT_DEFAULT_BIND_PORT_INT
     fi
-    run_process s-proxy "$SWIFT_DIR/bin/swift-proxy-server ${SWIFT_CONF_DIR}/proxy-server.conf -v"
+    run_process s-proxy "swift-proxy-server ${SWIFT_CONF_DIR}/proxy-server.conf -v"
     if [[ ${SWIFT_REPLICAS} == 1 ]]; then
         for type in object container account; do
-            run_process s-${type} "$SWIFT_DIR/bin/swift-${type}-server ${SWIFT_CONF_DIR}/${type}-server/1.conf -v"
+            run_process s-${type} "swift-${type}-server ${SWIFT_CONF_DIR}/${type}-server/1.conf -v"
         done
     fi