message: Fix vcx custom wallet path unit test for Android.
diff: @@ -443,6 +443,7 @@ pub fn send_message_to_agency(message: &A2AMessage, did: &str) -> VcxResult<Vec<
  #[cfg(test)]
  mod tests {
  + use std::env;
  use super::*;
  use utils::devsetup::*;
  use api::vcx::vcx_shutdown;
  @@ -453,11 +454,18 @@ mod tests {
  let agency_vk = "BcCSmgdfChLqmtBkkA26YotWVFBNnyY45WCnQziF4cqN";
  let host = "https://eas.pdev.evernym.com";
  let wallet_key = "test_key";
  +
  + let path = if cfg!(target_os = "android") {
  + env::var("EXTERNAL_STORAGE").unwrap() + "/tmp/custom1/"
  + } else {
  + "/tmp/custom1/".to_owned()
  + };
  +
  let config = json!({
  "wallet_name": "test_wallet",
  - "storage_config": "{
  - \"path\": \"/tmp/custom1\"
  - }",
  + "storage_config": json!({
  + "path": path
  + }).to_string(),
  "agency_url": host.to_string(),
  "agency_did": agency_did.to_string(),
  "agency_verkey": agency_vk.to_string(),
  @@ -466,7 +474,7 @@ mod tests {
  //Creates wallet at custom location
  connect_register_provision(&config.to_string()).unwrap();
  - std::path::Path::new("/tmp/custom1/test_wallet").exists();
  + assert!(std::path::Path::new(&(path + "test_wallet")).exists());
  vcx_shutdown(false);
  let my_config: Config = serde_json::from_str(&config.to_string()).unwrap();
  