Revert "Revert "Set crosvm as the default VMM for cuttlefish""

This reverts commit 460d158254a50db5c60b79fdfc08353bc17f7cb4.

Reason for revert: underlying reason for revert is fixed

Bug: 132986546
Change-Id: I9037a51286f37159182e0f27e147816f1e59839a
diff --git a/host/commands/launch/flags.cc b/host/commands/launch/flags.cc
index b1877d2..6c0867d 100644
--- a/host/commands/launch/flags.cc
+++ b/host/commands/launch/flags.cc
@@ -85,7 +85,7 @@
 DEFINE_string(instance_dir, "", // default handled on ParseCommandLine
               "A directory to put all instance specific files");
 DEFINE_string(
-    vm_manager, vm_manager::QemuManager::name(),
+    vm_manager, vm_manager::CrosvmManager::name(),
     "What virtual machine manager to use, one of {qemu_cli, crosvm}");
 DEFINE_string(
     gpu_mode, vsoc::kGpuModeGuestSwiftshader,