[VOL-2356]core log_level command line argument should take log level names not int value

- StringToLogLevel method returns two arguments.

Change-Id: I83d20d645fa63363e71265b163273414f14688a7
diff --git a/go.sum b/go.sum
index 3b37920..a40d1db 100644
--- a/go.sum
+++ b/go.sum
@@ -196,8 +196,8 @@
 github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
 github.com/onsi/gomega v1.4.2 h1:3mYCb7aPxS/RU7TI1y4rkEn1oKmPRjNJLNEXgw7MH2I=
 github.com/onsi/gomega v1.4.2/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
-github.com/opencord/voltha-lib-go/v3 v3.0.10 h1:y735YI2Pc4uKPGPoHWAtSqiiSkoAM2IYJcthcPkKolw=
-github.com/opencord/voltha-lib-go/v3 v3.0.10/go.mod h1:69Y+rVd25Nq2SUeoY7Q1BXtwrcUPllG0erhq+aK8Qec=
+github.com/opencord/voltha-lib-go/v3 v3.0.12 h1:YGpyjl0UxdVUpKuo/VO5eCi+1+5EbMK9ZUqjDvWUQWQ=
+github.com/opencord/voltha-lib-go/v3 v3.0.12/go.mod h1:69Y+rVd25Nq2SUeoY7Q1BXtwrcUPllG0erhq+aK8Qec=
 github.com/opencord/voltha-protos/v3 v3.2.3 h1:Wv73mw1Ye0bCfyhOk5svgrlE2tLizHq6tQluoDq9Vg8=
 github.com/opencord/voltha-protos/v3 v3.2.3/go.mod h1:RIGHt7b80BHpHh3ceodknh0DxUjUHCWSbYbZqRx7Og0=
 github.com/opencord/voltha-protos/v3 v3.2.4 h1:BTPpfwJslAY9UintQ9/f+wLD+StZ5QnPv6j7pbAk+J8=