Remove unused functions from devstack/lib/ovs

We don't need condinional ovs compilation since we run on Ubuntu Xenial.
This patch removes remaining bits that are not used by Neutron nor any
other big tent project.

Depends-On: Ia8f63b91334f73519878ba90957db84e7cf176f9
Change-Id: Icfa2eb0258af7c44638dcca688c1fa5ed343455a

devstack/lib/ovs

@@ -31,89 +31,6 @@ function load_module {
     fi
 }
 
-# is_kernel_supported_for_ovs25() - compilation of openvswitch 2.5 kernel module
-#                                   supports only kernels up to 4.3.x, function
-#                                   determines whether compilation from source
-#                                   will succeed on this machine
-function is_kernel_supported_for_ovs25 {
-    major=$(uname -r | cut -d\. -f 1)
-    minor=$(uname -r | cut -d\. -f 2)
-    if [ $major -le 3 ]; then
-        # All 3.x branches and lesser are supported
-        return 0
-    elif [ $major -eq 4 -a $minor -le 3 ]; then
-        # If it's version 4, minor must not be higher than 3
-        return 0
-    fi
-
-    return 1
-}
-
-# is_version_le() - Helper function to test if the first version string is less
-#                   than or equal to the second version string
-function is_version_le {
-    version1=$1
-    version2=$2
-    echo -e "$version1\\n$version2" | sort -VC
-    return $?
-}
-
-
-# is_kernel_supported_for_ovs261() - compilation of openvswitch 2.6.1 kernel
-#                                    module supports only kernels versions
-#                                    between 3.10 and 4.8 (inclusive)
-#                                    Taken from the OVS tree (acinclude.m4)
-function is_kernel_supported_for_ovs261 {
-    major=$(uname -r | cut -d\. -f 1)
-    minor=$(uname -r | cut -d\. -f 2)
-    kversion="$major.$minor"
-    minimum_version="3.10"
-    maximum_version="4.8"
-    if ! is_version_le $minimum_version $kversion; then
-        return 1
-    fi
-    if ! is_version_le $kversion $maximum_version ; then
-        return 1
-    fi
-    return 0
-}
-
-# is_ovs_version_ok() - Verify the OVS version is new enough. Specifically,
-#                       verify the OVS version >= 2.5.1
-function is_ovs_version_ok {
-    minimum_version="2.5.1"
-    version_string=$(ovs-vswitchd -V | awk '/^ovs-vswitchd/ { print $NF}')
-    is_version_le $minimum_version $version_string
-    return $?
-}
-
-# upgrade_ovs_if_necessary() - Check if OVS version is high enough ( >= 2.5.1)
-#                              and upgrade if necessary.
-#                              Accepts one optional parameter for kernel modules compilation:
-#                                 - first parameter is True by default and it means OVS will be
-#                                   compiled with kernel modules. False won't compile kernel modules.
-function upgrade_ovs_if_necessary {
-    local compile_modules=${1:-True}
-    if ! is_ovs_version_ok; then
-        if [ "$NEUTRON_OVERRIDE_OVS_BRANCH" ]; then
-            OVS_BRANCH=$NEUTRON_OVERRIDE_OVS_BRANCH
-        elif is_kernel_supported_for_ovs25; then
-            # The order of conditions here is such that on Trusty we install
-            # version 2.5.1, and on Xenial we upgrade to 2.6.1 (Since Xenial
-            # kernel is not compatible with 2.5.1)
-            OVS_BRANCH="v2.5.1"
-        elif is_kernel_supported_for_ovs261; then
-            OVS_BRANCH="v2.6.1"
-        else
-            echo "WARNING: Unsupported kernel for OVS compilation. Trying default branch."
-        fi
-        echo "Compiling OVS branch: $OVS_BRANCH"
-        remove_ovs_packages
-        compile_ovs $compile_modules /usr /var
-        start_new_ovs
-    fi
-}
-
 # prepare_for_compilation() - Fetch ovs git repository and install packages needed for
 #                             compilation.
 function prepare_for_compilation {