only soft enforce requirements not in projects.txt

We're adding the ability to have devstack plugins, which should be
much more free to require new things not in global requirements. Our
old thinking of locking down all the requirements doesn't really work
in a plugin model.

Instead, if the project is in projects.txt, continue with the old
behavior. If it is not, do a soft update (update all the requirements
we know about, leave the ones we don't). This was previously the SOFT
requirements update mode, but now it will just be the default.

Change-Id: Ic0c6e01a6d7613d712ac9e7e4a378cc3a8ce75e6
diff --git a/inc/python b/inc/python
index e3c5e61..07a811e 100644
--- a/inc/python
+++ b/inc/python
@@ -216,18 +216,14 @@
     local update_requirements=$(cd $project_dir && git diff --exit-code >/dev/null || echo "changed")
 
     if [[ $update_requirements != "changed" ]]; then
-        if [[ "$REQUIREMENTS_MODE" == "soft" ]]; then
-            if is_in_projects_txt $project_dir; then
-                (cd $REQUIREMENTS_DIR; \
-                    ./.venv/bin/python update.py $project_dir)
-            else
-                # soft update projects not found in requirements project.txt
-                (cd $REQUIREMENTS_DIR; \
-                    ./.venv/bin/python update.py -s $project_dir)
-            fi
-        else
+        if is_in_projects_txt $project_dir; then
             (cd $REQUIREMENTS_DIR; \
                 ./.venv/bin/python update.py $project_dir)
+        else
+            # soft update projects not found in requirements project.txt
+            echo "$project_dir not a constrained repository, soft enforcing requirements"
+            (cd $REQUIREMENTS_DIR; \
+                ./.venv/bin/python update.py -s $project_dir)
         fi
     fi
 
diff --git a/stackrc b/stackrc
index 1ac1338..9cd9c05 100644
--- a/stackrc
+++ b/stackrc
@@ -149,17 +149,6 @@
 # Zero disables timeouts
 GIT_TIMEOUT=${GIT_TIMEOUT:-0}
 
-# Requirements enforcing mode
-#
-# - strict (default) : ensure all project requirements files match
-#   what's in global requirements.
-#
-# - soft : enforce requirements on everything in
-#   requirements/projects.txt, but do soft updates on all other
-#   repositories (i.e. sync versions for requirements that are in g-r,
-#   but pass through any extras)
-REQUIREMENTS_MODE=${REQUIREMENTS_MODE:-strict}
-
 
 # Repositories
 # ------------