Remove 'egrep' and use 'grep -E' instead.

[brianonn]

The command 'egrep' (and 'fgrep') has been deprecated since 2007. GNU egrep 3.8+ now prints a warning that 'egrep' is deprecated and this warning appears in the gvm command output.

It has been over 16 years since 'egrep' and 'fgrep' were deprecated and it's time to stop using them. Furthermore, POSIX does not even include an 'egrep' or 'fgrep' command, only 'grep'.