Revert "Allow properly overriding DEST"

After I00847bb6733febf105855ae6fc577a7c904ec4b4, we cannot see the
test result (testr_result.html) on gate jobs.
So let's revert the patch for verifying the test result on the gate.

Change-Id: I9db1ff9f43b22d1634a43c7d5e502cc205aa26f2
Closes-Bug: #1617476
diff --git a/stackrc b/stackrc
index f7bdbc2..c14085a 100644
--- a/stackrc
+++ b/stackrc
@@ -16,6 +16,15 @@
 # Destination path for installation
 DEST=/opt/stack
 
+# Destination for working data
+DATA_DIR=${DEST}/data
+
+# Destination for status files
+SERVICE_DIR=${DEST}/status
+
+# Path for subunit output file
+SUBUNIT_OUTPUT=${DEST}/devstack.subunit
+
 # Determine stack user
 if [[ $EUID -eq 0 ]]; then
     STACK_USER=stack
@@ -121,15 +130,6 @@
     source $RC_DIR/.localrc.auto
 fi
 
-# Destination for working data
-DATA_DIR=${DATA_DIR:-$DEST/data}
-
-# Destination for status files
-SERVICE_DIR=${SERVICE_DIR:-$DEST/status}
-
-# Path for subunit output file
-SUBUNIT_OUTPUT=${SUBUNIT_OUTPUT:-$DEST/devstack.subunit}
-
 # Default for log coloring is based on interactive-or-not.
 # Baseline assumption is that non-interactive invocations are for CI,
 # where logs are to be presented as browsable text files; hence color