ENH: add some extra checks in gh-pages script

Check that directory to upload exists, contains an index.html, and does
not contain a current .git directory.

Author: matthew-brett

tools/upload-gh-pages.sh

@@ -6,6 +6,14 @@ if [ -z "$HTML_DIR" ]; then
     echo $USAGE
     exit 1
 fi
+if [ ! -e "$HTML_DIR/index.html" ]; then
+    echo "$HTML_DIR does not contain an index.html"
+    exit 1
+fi
+if [ -d "$HTML_DIR/.git" ]; then
+    echo "$HTML_DIR already contains a .git directory"
+    exit 1
+fi
 PROJECT=$2
 if [ -z "$PROJECT" ]; then
     echo $USAGE