[MINOR] Handle fact that mv is different on linux, mac
[MINOR] Handle fact that mv is different on linux, mac

Follow up to https://github.com/apache/spark/commit/ae853e8f3bdbd16427e6f1ffade4f63abaf74abb as `mv` throws an error on the Jenkins machines if source and destinations are the same.

Author: Shivaram Venkataraman <ad63b47dfac1951bde2b661ba9fbbe123f686bee@cs.berkeley.edu>

Closes #16302 from shivaram/sparkr-no-mv-fix.

(cherry picked from commit 5a44f18a2a114bdd37b6714d81f88cb68148f0c9)
Signed-off-by: Shivaram Venkataraman <ad63b47dfac1951bde2b661ba9fbbe123f686bee@cs.berkeley.edu>

metamx/spark,Panos-Bletsos/spark-cost-model-optimizer,kimoonkim/spark,big-pegasus/spark,metamx/spark,Panos-Bletsos/spark-cost-model-optimizer,metamx/spark,kimoonkim/spark,big-pegasus/spark,kimoonkim/spark,ibm-research-ireland/sparkoscope,metamx/spark,ibm-research-ireland/sparkoscope,ibm-research-ireland/sparkoscope,SnappyDataInc/spark,kimoonkim/spark,big-pegasus/spark,huang1900/spark,huang1900/spark,SnappyDataInc/spark,SnappyDataInc/spark,ibm-research-ireland/sparkoscope,ibm-research-ireland/sparkoscope,big-pegasus/spark,SnappyDataInc/spark,huang1900/spark,metamx/spark,kimoonkim/spark,SnappyDataInc/spark,metamx/spark,kimoonkim/spark,kimoonkim/spark,ibm-research-ireland/sparkoscope,Panos-Bletsos/spark-cost-model-optimizer,ibm-research-ireland/sparkoscope,SnappyDataInc/spark,Panos-Bletsos/spark-cost-model-optimizer,big-pegasus/spark,huang1900/spark,huang1900/spark,big-pegasus/spark,metamx/spark,huang1900/spark,SnappyDataInc/spark,Panos-Bletsos/spark-cost-model-optimizer,Panos-Bletsos/spark-cost-model-optimizer,big-pegasus/spark,Panos-Bletsos/spark-cost-model-optimizer,huang1900/spark