[KYUUBI #6175] [MINOR] Refactor copy path about SPARK_HOME in docker

# 🔍 Description
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## Types of changes 🔖

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- [ ] New feature (non-breaking change which adds functionality)
- [ ] Breaking change (fix or feature that would cause existing functionality to change)

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**Be nice. Be informative.**

Closes #6175 from yanghua/docker-minor-refactor.

Closes #6175

e5c2636 [yanghua] Refactor copy path about SPARK_HOME in docker

Authored-by: yanghua <[email protected]>
Signed-off-by: Cheng Pan <[email protected]>

bin/docker-image-tool.sh

@@ -110,7 +110,7 @@ function build {
         error "Cannot found dir SPARK_HOME $SPARK_HOME, you must configure SPARK_HOME correct."
       fi
     fi
-    cp -r "$SPARK_HOME/." "$KYUUBI_ROOT/spark-binary/"
+    cp -r "$SPARK_HOME"/* "$KYUUBI_ROOT"/spark-binary/
   fi
 
   # Verify that the Docker image content directory is present