Extract "pkg/version".PrintAndExitIfRequested() to its own package

because it causes a runtime panic if a binary which has its own implementation
of "-version" flag tries to reuse a package library which indirectly depend on
"pkg/version".

e.g. If such an user-defined binary tires to link "pkg/api" or "pkg/client",
the binary fails with a runtime panic "flag redefined: version".

pkg/version/version.go

@@ -17,13 +17,7 @@ limitations under the License.
 package version
 
 import (
-	"flag"
 	"fmt"
-	"os"
-)
-
-var (
-	versionFlag = flag.Bool("version", false, "Print version information and quit")
 )
 
 // Info contains versioning information.
@@ -49,12 +43,3 @@ func Get() Info {
 func (info Info) String() string {
 	return fmt.Sprintf("version %s.%s, build %s", info.Major, info.Minor, info.GitCommit)
 }
-
-// PrintAndExitIfRequested will check if the -version flag was passed
-// and, if so, print the version and exit.
-func PrintAndExitIfRequested() {
-	if *versionFlag {
-		fmt.Printf("Kubernetes %s\n", Get())
-		os.Exit(0)
-	}
-}