Plik segfaults when MaxTTL is set to -1 and DefaultTTL is a valid int

[rhass]

I upgraded to v1.3.1 and my previous config values resulted in the server crashing while parsing the config file.
The values which angered it were:

DefaultTTL          = 604800        # 7 days
MaxTTL              = -1            # -1 => No limit

The resulting error was as follows:

Unable to read config file : DefaultTTL should not be more than MaxTTL
panic: runtime error: invalid memory address or nil pointer dereference
[signal SIGSEGV: segmentation violation code=0x1 addr=0x0 pc=0x859506]

goroutine 1 [running]:
github.com/root-gg/plik/server/common.(*Configuration).NewLogger(0x0, 0xc000377410)
	/go/src/github.com/root-gg/plik/server/common/config.go:173 +0x26
github.com/root-gg/plik/server/server.(*PlikServer).start(0xc000366240, 0xc00033fcb0, 0x410158)
	/go/src/github.com/root-gg/plik/server/server/server.go:82 +0x65
github.com/root-gg/plik/server/server.(*PlikServer).Start(0xc000366240, 0x0, 0x0)
	/go/src/github.com/root-gg/plik/server/server/server.go:78 +0xde
github.com/root-gg/plik/server/cmd.startPlikServer(0x13472e0, 0xc0002311e0, 0x0, 0x2)
	/go/src/github.com/root-gg/plik/server/cmd/root.go:145 +0x9d
github.com/spf13/cobra.(*Command).execute(0x13472e0, 0xc000032190, 0x2, 0x2, 0x13472e0, 0xc000032190)
	/go/pkg/mod/github.com/spf13/cobra@v0.0.6-0.20200106181057-89c7ffb5129b/command.go:835 +0x2c2
github.com/spf13/cobra.(*Command).ExecuteC(0x13472e0, 0x44764a, 0x135da20, 0xc000000180)
	/go/pkg/mod/github.com/spf13/cobra@v0.0.6-0.20200106181057-89c7ffb5129b/command.go:919 +0x30b
github.com/spf13/cobra.(*Command).Execute(...)
	/go/pkg/mod/github.com/spf13/cobra@v0.0.6-0.20200106181057-89c7ffb5129b/command.go:869
github.com/root-gg/plik/server/cmd.Execute()
	/go/src/github.com/root-gg/plik/server/cmd/root.go:36 +0x31
main.main()
	/go/src/github.com/root-gg/plik/server/main.go:6 +0x25