Fix path handling in download-mongodb (#498)

Co-authored-by: Ezra Chung <88335979+eramongodb@users.noreply.github.com>

.evergreen/download-mongodb.sh

@@ -688,25 +688,29 @@ set_url_win32 ()
   MONGODB_24="https://fastdl.mongodb.org/win32/mongodb-win32-i386${DEBUG}-${VERSION_24}.zip"
 }
 
+# curl_retry emulates running curl with `--retry 5` and `--retry-all-errors`.
+curl_retry ()
+{
+  for i in 1 2 4 8 16; do
+    { curl --fail -sS --max-time 300 "$@" && return 0; } || sleep $i
+  done
+  return 1
+}
 
 # download_and_extract_package downloads a MongoDB server package.
 download_and_extract_package ()
 {
    MONGODB_DOWNLOAD_URL=$1
    EXTRACT=$2
 
-   # shellcheck disable=SC3028
-   SCRIPT_DIR=$(dirname ${BASH_SOURCE:-$0})
-   . $SCRIPT_DIR/handle-paths.sh
-
    if [ -n "${MONGODB_BINARIES:-}" ]; then
       cd "$(dirname "$(dirname "${MONGODB_BINARIES:?}")")"
    else
       cd $DRIVERS_TOOLS
    fi
 
    echo "Installing server binaries..."
-   "$SCRIPT_DIR/retry-with-backoff.sh" curl $MONGODB_DOWNLOAD_URL --output mongodb-binaries.tgz
+   curl_retry $MONGODB_DOWNLOAD_URL --output mongodb-binaries.tgz
 
    $EXTRACT mongodb-binaries.tgz
    echo "Installing server binaries... done."
@@ -727,10 +731,6 @@ download_and_extract_mongosh ()
    MONGOSH_DOWNLOAD_URL=$1
    EXTRACT_MONGOSH=${2:-"tar zxf"}
 
-   # shellcheck disable=SC3028
-   SCRIPT_DIR=$(dirname ${BASH_SOURCE:-$0})
-   . $SCRIPT_DIR/handle-paths.sh
-
    if [ -z "$MONGOSH_DOWNLOAD_URL" ]; then
       get_mongodb_download_url_for "$(get_distro)" latest false
    fi
@@ -742,7 +742,7 @@ download_and_extract_mongosh ()
    fi
 
    echo "Installing MongoDB shell..."
-   "$SCRIPT_DIR/retry-with-backoff.sh" curl $MONGOSH_DOWNLOAD_URL --output mongosh.tgz
+   curl_retry $MONGOSH_DOWNLOAD_URL --output mongosh.tgz
    $EXTRACT_MONGOSH mongosh.tgz
 
    rm -f mongosh.tgz
@@ -771,10 +771,6 @@ download_and_extract ()
       download_and_extract_mongosh "$MONGOSH_DOWNLOAD_URL" "$EXTRACT_MONGOSH"
    fi
 
-   # shellcheck disable=SC3028
-   SCRIPT_DIR=$(dirname ${BASH_SOURCE:-$0})
-   . $SCRIPT_DIR/handle-paths.sh
-
    if [ ! -z "${INSTALL_LEGACY_SHELL:-}" ] && [ ! -e $DRIVERS_TOOLS/mongodb/bin/mongo ] && [ ! -e $DRIVERS_TOOLS/mongodb/bin/mongo.exe ]; then
       # The legacy mongo shell is not included in server downloads of 6.0.0-rc6 or later. Refer: SERVER-64352.
       # Some test scripts use the mongo shell for setup.
@@ -829,10 +825,7 @@ download_and_extract_crypt_shared ()
    mkdir crypt_shared_download
    cd crypt_shared_download
 
-   # shellcheck disable=SC3028
-   SCRIPT_DIR=$(dirname ${BASH_SOURCE:-$0})
-   . $SCRIPT_DIR/handle-paths.sh
-   "$SCRIPT_DIR/retry-with-backoff.sh" curl $MONGO_CRYPT_SHARED_DOWNLOAD_URL --output crypt_shared-binaries.tgz
+   curl_retry $MONGO_CRYPT_SHARED_DOWNLOAD_URL --output crypt_shared-binaries.tgz
    $EXTRACT crypt_shared-binaries.tgz
 
    LIBRARY_NAME="mongo_crypt_v1"