[CI/CD] Changed order of the S3 bucket mount step in deb builds.

It seems that s3fs may fail if two clients try to mount the same
resource with the same token at the same time.

.drone.yml

@@ -466,6 +466,11 @@ steps:
     - apt update
     - apt install -y curl dpkg-dev gpg git python3 python3-pip s3fs
 
+    - echo "-- Mounting the S3 bucket"
+    - mkdir -p "$BUCKET_MNT"
+    - s3fs "$S3_BUCKET" "$BUCKET_MNT" -o url="$AWS_ENDPOINT_URL"
+    - export APT_ROOT="$BUCKET_MNT/apt"
+
     - echo "--- Parsing metadata"
     - git config --global --add safe.directory $PWD
     - git pull --rebase origin master --tags
@@ -495,11 +500,6 @@ steps:
       EOF
     - dpkg --build "$GIT_BUILD_DIR"
 
-    - echo "-- Mounting the S3 bucket"
-    - mkdir -p "$BUCKET_MNT"
-    - s3fs "$S3_BUCKET" "$BUCKET_MNT" -o url="$AWS_ENDPOINT_URL"
-    - export APT_ROOT="$BUCKET_MNT/apt"
-
     - echo "--- Pushing package to the S3 bucket"
     - mkdir -p "$APT_ROOT/pool/$DEB_VERSION/dev"
     - cp "$GIT_DEB" "$APT_ROOT/pool/$DEB_VERSION/dev/"