Delete any old clone of SU2 repository

Signed-off-by: Martin Tzvetanov Grigorov <mgrigorov@apache.org>

Author: martin-g

build/compileSU2.sh

@@ -44,6 +44,9 @@ if [ ! -z "$branch" ]; then
     mkdir "src"
   fi
   cd "src"
+  if [ -d $name ]; then
+    rm -rf $name
+  fi
   git clone --recursive --depth=1 --shallow-submodules https://github.com/su2code/SU2 $name
   cd $name
   git config --add remote.origin.fetch '+refs/pull/*/merge:refs/remotes/origin/refs/pull/*/merge'