Next attempt for issue #709 fix

Now creates icon cache directory at startup.
And it also creates the directory if it went missing during runtime.
Also modified the icon_save/mark_negcache to be one.

src/main.rs

@@ -25,6 +25,7 @@ extern crate num_derive;
 use std::{
     path::Path,
     process::{exit, Command},
+    fs::create_dir_all,
 };
 
 #[macro_use]
@@ -52,6 +53,8 @@ fn main() {
     check_web_vault();
     migrations::run_migrations();
 
+    create_icon_cache_folder();
+
     launch_rocket();
 }
 
@@ -129,8 +132,7 @@ fn check_db() {
         let path = Path::new(&url);
 
         if let Some(parent) = path.parent() {
-            use std::fs;
-            if fs::create_dir_all(parent).is_err() {
+            if create_dir_all(parent).is_err() {
                 error!("Error creating database directory");
                 exit(1);
             }
@@ -148,6 +150,11 @@ fn check_db() {
     db::get_connection().expect("Can't connect to DB");
 }
 
+fn create_icon_cache_folder() {
+    // Try to create the icon cache folder, and generate an error if it could not.
+    create_dir_all(&CONFIG.icon_cache_folder()).expect("Error creating icon cache directory");
+}
+
 fn check_rsa_keys() {
     // If the RSA keys don't exist, try to create them
     if !util::file_exists(&CONFIG.private_rsa_key()) || !util::file_exists(&CONFIG.public_rsa_key()) {