Fix finding ChangeLog when building

Keep the first optional argument of get_version.sh as "--strict" and
make the second the PROJECT_SOURCE_DIR plus trailing slash from
CMakeLists.txt

get_version.sh

@@ -33,10 +33,10 @@ then
     fi
     VERSION=$(git describe --exact-match 2>/dev/null || echo "$MAJOR-git$(git show -s --pretty=format:%ci | cut -d ' ' -f 1 | tr -d '-').$(git show -s --pretty=format:%h)")$DIRTY
 else
-    VERSION=$( (head -n 1 ChangeLog || head -n 1 ../ChangeLog) | cut -d ' ' -f 2)
+    VERSION=$(head -n 1 ${2}ChangeLog | cut -d ' ' -f 2)
     if [ $VERSION = "master" ]
     then
-        VERSION=$VERSION-$( (head -n 1 ChangeLog || head -n 1 ../ChangeLog) | cut -d ' ' -f 1)
+        VERSION=$VERSION-$(head -n 1 ${2}ChangeLog | cut -d ' ' -f 1)
     fi
 fi