Fix local res in tue-install-git

Author: MatthijsBurgh

installer/tue-install-impl.bash

@@ -378,6 +378,7 @@ function tue-install-git
         tue-install-error "Target directory path cannot be empty"
     fi
 
+    local res
     if [ ! -d "$targetdir" ]
     then
         tue-install-debug "git clone --recursive $repo $targetdir"
@@ -403,7 +404,6 @@ function tue-install-git
                 tue-install-info "URL has switched to $repo"
             fi
 
-            local res
             tue-install-debug "git -C $targetdir pull --ff-only --prune"
             res=$(git -C "$targetdir" pull --ff-only --prune 2>&1)
             tue-install-debug "res: $res"