Add download retry helper on Ubuntu (#955)

* Add download retry helper

images/linux/scripts/helpers/install.sh

@@ -0,0 +1,30 @@
+#!/bin/bash
+################################################################################
+##  File:  install.sh
+##  Desc:  Helper functions for installing tools
+################################################################################
+
+download_with_retries() {
+# Due to restrictions of bash functions, positional arguments are used here.
+# In case if you using latest argument NAME, you should also set value to all previous parameters.
+# Example: download_with_retries $ANDROID_SDK_URL "." "android_sdk.zip"
+    local URL="$1"
+    local DEST="${2:-.}"
+    local NAME="${3:-${URL##*/}}"
+
+    echo "Downloading $URL..."
+    i=20
+    while [ $i -gt 0 ]; do
+        ((i--))
+        wget $URL   --output-document="$DEST/$NAME" \
+                    --no-verbose
+        if [ $? != 0 ]; then
+            sleep 30
+        else
+            return 0
+        fi
+    done
+
+    echo "Could not download $URL"
+    return 1
+}