Fix logger line() call if built outside of the repo root

If harbor is built (or `go test`'d) in a different folder than the repo
root, the call to common/utils/log/line(...) will panic with an index
out of range runtime error because the separator can't find `harbor/src`
in the path.

Signed-off-by: Nathan Lowe <public@nlowe.me>

src/common/utils/log/logger.go

@@ -278,7 +278,7 @@ func line(callDepth int) string {
 		line = 0
 	}
 	l := strings.SplitN(file, srcSeparator, 2)
-	if len(l) > 0 {
+	if len(l) > 1 {
 		file = l[1]
 	}
 	return fmt.Sprintf("[%s:%d]:", file, line)