Use modprobe.d for dynamically loaded modules

[webbaker0226]

In the initial implementation of fdrd, if the probes to be enabled are in a loadable module, fdrd forces you to use a modprobe verb in the config file to load the module first, so it can insert the probes. This is not ideal. modprobe does provide a mechanism for dealing with actions that need to be performed when a module is loaded. See modprobe.d(5) for more details.

The general idea is that an entry is created in one of the modprobe.d directories so that when the module is loaded, the script posts a signal to fdrd, which then determines if some deferred probes can now be enabled.