Opportunistically use a matching kernel version for building the modules (#1138)

When building the team kernel module (and others), if a matching source
kernel version exists, then make sure we use that exact version. This
avoids the case where we end up pulling the sources for a newer kernel
version when a matching one exists.

Signed-off-by: Saikrishna Arcot <sarcot@microsoft.com>

Author: saiarcot895

.azure-pipelines/build_and_install_module.sh

@@ -54,8 +54,10 @@ build_and_install_kmodule()
             "can be loaded into the kernel or function correctly. If possible, please update your kernel and reboot " \
             "your system so that it's running the matching kernel version." >&2
         echo "Continuing with the build anyways" >&2
+        apt-get source "linux-image-unsigned-${KERNEL_RELEASE}"
+    else
+        apt-get source "linux-image-unsigned-${KERNEL_RELEASE}=${KERNEL_PACKAGE_VERSION}"
     fi
-    apt-get source "linux-image-unsigned-${KERNEL_RELEASE}"
 
     # Recover the original apt sources list
     cp /etc/apt/sources.list.bk /etc/apt/sources.list