hypervisor: drop get_api_version from Hypervisor trait

The new function already checks if the API version is compatible. There
is no need to expose the get_api_version function to code outside
hypervisor crate.

Signed-off-by: Wei Liu <liuwe@microsoft.com>

hypervisor/src/kvm/mod.rs

@@ -424,12 +424,6 @@ impl hypervisor::Hypervisor for KvmHypervisor {
         Ok(())
     }
 
-    ///
-    /// Returns the KVM API version.
-    ///
-    fn get_api_version(&self) -> i32 {
-        self.kvm.get_api_version()
-    }
     ///
     ///  Returns the size of the memory mapping required to use the vcpu's `kvm_run` structure.
     ///