fix TestLogAndMetrics

[swagatbora90]

Issue #, if available:
TestLogAndMetrics/Error currently fails with Error

=== CONT  TestLogAndMetrics/Error
    machine_test.go:469:
        	Error Trace:	/local/home/buildkite-agent/builds/ip-10-0-0-92-30/firecracker-microvm/firecracker-go-sdk-amd/machine_test.go:469
        	Error:      	Expect "" to match "^Running Firecracker v\d+\.\d+[\.-]"
        	Test:       	TestLogAndMetrics/Error

After looking into the code, looks like there has been a recent change in Firecracker to fix the logger behavior. firecracker-microvm/firecracker#4171. After the change, the log-level passed to Firecracker is respected, so when we pass "Error" loglevel, the info message does not get printed

Description of changes:
The "Running Firecracker v\d+.\d+[.-]" log should be written to fc.logs when loglevel is set to INFO

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.