M #-: Add Travis test for conf branch protection

OpenNebula maintenance and hotfix revisions do not allow for any
change in their configuration files with respect to their
previous version.

In a minor branch (one-XX), the new 01-conf_branch_protect.sh script
will warn about configuration changes.

.travis/tests/01-conf_branch_protect.sh

@@ -0,0 +1,40 @@
+#!/bin/bash -xv
+
+# **previous** refers to the code base in the main repository
+# **current**  refers to the code base of the PR (or the new commit)
+
+if [[ $TRAVIS_BRANCH =~ (^one-) ]]; then
+    export PREVIOUS_ONE=~/previous.one
+    export CURRENT_ONE=$TRAVIS_BUILD_DIR
+    export PREVIOUS_ONE_INSTALL=~/previous.install
+    export CURRENT_ONE_INSTALL=~/current.install
+
+    # Checkout previous code base
+    git clone https://github.com/tinova/one $PREVIOUS_ONE
+    (cd $PREVIOUS_ONE ; git checkout $TRAVIS_BRANCH)
+    # In a PR we compare with the head of $TRAVIS_BRANCH
+    # Otherwise, we want to check with the previous commit
+    if [[ $TRAVIS_PULL_REQUEST == false ]]; then
+        (cd $PREVIOUS_ONE ; git checkout HEAD~1)
+    fi
+
+    # Debug information
+    echo "Previous commit:"
+    (cd $PREVIOUS_ONE ; git --no-pager log -1)
+    echo "----------------"
+    echo "Current commit:"
+    (cd $CURRENT_ONE ; git --no-pager log -1)
+    echo "----------------"
+
+    # Install previous and current code base
+    (cd $PREVIOUS_ONE ; ./install.sh -d $PREVIOUS_ONE_INSTALL &> /dev/null)
+    (cd $CURRENT_ONE  ; ./install.sh -d $CURRENT_ONE_INSTALL &> /dev/null)
+
+    echo "Testing conf changes:"
+    diff -r $PREVIOUS_ONE_INSTALL/etc $CURRENT_ONE_INSTALL/etc
+    rc=$?; if [[ $rc != 0 ]]; then exit $rc; fi
+    diff -r $PREVIOUS_ONE_INSTALL/var/remotes/etc $CURRENT_ONE_INSTALL/var/remotes/etc
+    rc=$?; if [[ $rc != 0 ]]; then exit $rc; fi
+fi
+
+exit 0