chore(commands): Remove obsolete code

The code has become obsolete because since 3cfe66e the VCS plugins do
not implement `CommandLineTool` anymore.

Signed-off-by: Martin Nonnenmacher <martin.nonnenmacher@bosch.com>

Author: mnonnenmacher

plugins/commands/requirements/src/main/kotlin/RequirementsCommand.kt

@@ -35,7 +35,6 @@ import kotlin.reflect.full.companionObjectInstance
 import org.apache.logging.log4j.kotlin.logger
 
 import org.ossreviewtoolkit.analyzer.PackageManager
-import org.ossreviewtoolkit.downloader.VersionControlSystem
 import org.ossreviewtoolkit.model.config.AnalyzerConfiguration
 import org.ossreviewtoolkit.model.config.RepositoryConfiguration
 import org.ossreviewtoolkit.plugins.api.OrtPlugin
@@ -215,12 +214,6 @@ class RequirementsCommand(
                         )
                     }
 
-                    VersionControlSystem::class.java.isAssignableFrom(it) -> {
-                        category = "VersionControlSystem"
-                        logger.debug { "$it is a $category." }
-                        it.getDeclaredConstructor().newInstance()
-                    }
-
                     else -> {
                         logger.debug { "Trying to instantiate $it without any arguments." }
                         it.getDeclaredConstructor().newInstance()