Unary operator expected when checking patch result.

[Jackie9527]

Here is the error logs.

--------------- Cloning bzip2 1.0.8 and building ---------------

fatal: destination path 'bzip2' already exists and is not an empty directory.
/home/jackie/o3de/3p-package-source/package-system/python/linux_x64/temp/bzip2 /home/jackie/o3de/3p-package-source/package-system/python/linux_x64/temp
Applying patch file /home/jackie/o3de/3p-package-source/package-system/python/linux_x64/open3d_bzip2.patch

/home/jackie/o3de/3p-package-source/package-system/python/linux_x64/make-python.sh: line 88: [: -ne: unary operator expected

No value is assigned to retVal.
Below is the code.

3p-package-source/package-system/python/linux_x64/make-python.sh

Lines 86 to 90 in f5ecfa5

	echo Applying patch file $PATCH_FILE
	git apply --ignore-whitespace $PATCH_FILE
	if [ $retVal -ne 0 ]; then
	echo "Git apply failed"
	exit $retVal