test eventlog: fix check eventlog.sh if efivar.h exists #1682

Job	Run time
coverage-test	5m 45s
master-tss-build-test (gcc)	17m 52s
coverity-test	0s
master-tss-build-test (clang)	5m 3s
build-test (ubuntu-18.04, gcc)	5m 59s
build-test (ubuntu-18.04, clang)	4m 59s
build-test (ubuntu-20.04, gcc)	5m 48s
build-test (ubuntu-20.04, clang)	5m 2s
build-test (fedora-30, gcc)	5m 52s
build-test (fedora-30, clang)	5m 18s
build-test (opensuse-leap, gcc)	6m 0s
build-test (opensuse-leap, clang)	5m 14s
build-test (fedora-32, gcc)	5m 53s
build-test (fedora-32, clang)	5m 9s
build-test (ubuntu-22.04, gcc)	11m 15s
build-test (ubuntu-22.04, clang)	10m 42s
	1h 45m 51s

Provide feedback