Update patch-realsense-ubuntu-xenial.sh

Modify it in order to support both 4.4.xx and 4.8.xx kernel versions.

My name is Zhe Hu.
I agree to the terms of the Intel® RealSense™ Cross Platform API CLA.

scripts/patch-realsense-ubuntu-xenial.sh

@@ -21,7 +21,18 @@ LINUX_BRANCH=$(uname -r)
 kernel_name="ubuntu-xenial"
 
 # Download the latest the linux kernel sources from ubuntu-xenial tree
-[ ! -d ${kernel_name} ] && git clone git://kernel.ubuntu.com/ubuntu/ubuntu-xenial.git --depth 1
+# If LINUX_BRANCH is 4.8.xx
+if [ "${LINUX_BRANCH:0:4}" == "4.8." ];
+then
+	[ ! -d ${kernel_name} ] && git clone git://kernel.ubuntu.com/ubuntu/ubuntu-xenial.git --depth 1 -b hwe  --single-branch
+# If LINUX_BRANCH is 4.4.xx
+elif [ "${LINUX_BRANCH:0:4}" == "4.4." ];
+then
+	[ ! -d ${kernel_name} ] && git clone git://kernel.ubuntu.com/ubuntu/ubuntu-xenial.git --depth 1
+else
+	echo -e "\e[41mKernel Version: $LINUX_BRANCH is not officially supported.Please change it to 4.8.xx or 4.4.xx\e[0m"
+	exit 1
+fi
 cd ${kernel_name}
 
 # Verify that there are no trailing changes., warn the user to make corrective action if needed
@@ -43,7 +54,15 @@ then
 		printf "Resetting local changes in %s folder\n " ${kernel_name}
 		git reset --hard
 		echo -e "\e[32mUpdate the folder content with the latest from mainline branch\e[0m"
-		git pull origin master
+		if [ "${LINUX_BRANCH:0:4}" == "4.8." ];
+		then
+			git pull origin hwe --depth 1
+		fi
+		if [ "${LINUX_BRANCH:0:4}" == "4.4." ];
+		then
+			git pull origin master
+		fi		
+
 	fi
 fi