new kernel check should check for a kernel

[benformosa]

I've noticed that tracer incorrectly reports that a new kernel is available on systems which have kernel modules installed for other kernel versions.

I have a RHEL 7.6 system with CommVault agent installed, which has installed a kernel module for every kernel supported by that software.
See https://documentation.commvault.com/commvault/v11/article?p=1940.htm

I have two kernels installed, and am running the latest:

$ rpm -qa kernel
kernel-3.10.0-957.21.2.el7.x86_64
kernel-3.10.0-957.21.3.el7.x86_64
$ uname -r
3.10.0-957.21.3.el7.x86_64

Here's the contents of the modules directory for the latest kernel:

$ find /lib/modules/$(uname -r) -maxdepth 1
/lib/modules/3.10.0-957.21.3.el7.x86_64
/lib/modules/3.10.0-957.21.3.el7.x86_64/build
/lib/modules/3.10.0-957.21.3.el7.x86_64/extra
/lib/modules/3.10.0-957.21.3.el7.x86_64/kernel
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.block
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.builtin
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.drm
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.modesetting
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.networking
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.order
/lib/modules/3.10.0-957.21.3.el7.x86_64/source
/lib/modules/3.10.0-957.21.3.el7.x86_64/updates
/lib/modules/3.10.0-957.21.3.el7.x86_64/vdso
/lib/modules/3.10.0-957.21.3.el7.x86_64/weak-updates
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.dep
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.dep.bin
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.symbols
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.symbols.bin
/lib/modules/3.10.0-957.21.3.el7.x86_64/weak
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.builtin.bin
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.alias
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.alias.bin
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.softdep
/lib/modules/3.10.0-957.21.3.el7.x86_64/modules.devname

And here's the contents of the modules directory for what tracer detects as a newer kernel:

$ find /lib/modules/3.12.49-11-default
/lib/modules/3.12.49-11-default
/lib/modules/3.12.49-11-default/extra
/lib/modules/3.12.49-11-default/extra/cdr.ko
/lib/modules/3.12.49-11-default/extra/cvblk.ko
/lib/modules/3.12.49-11-default/extra/cvbf.ko

Here's an idea of a fix to check for the presence of a 'kernel' directory.
https://github.com/FrostyX/tracer/blob/master/tracer/resources/tracer.py#L132

def _has_updated_kernel(self):
    if os.path.isdir('/lib/modules/'):
            for k_version in next(os.walk('/lib/modules/'))[1]:
                    if parse_version(os.uname()[2]) < parse_version(k_version) and os.path.isdir(os.path.join('/lib/modules/', k_version, 'kernel')):
                            return True
            return False
    return False