Convert fastboot/libsnapshot to new BootControl client

Thew new client will use AIDL if available, and fallback to HIDL
otherwise.

Test: th
Bug: 227536004
Change-Id: I9af21037a76a4a6db00144f5b2774ea23f3a5cc2
diff --git a/fastboot/device/utility.cpp b/fastboot/device/utility.cpp
index 3302c43..e12ee64 100644
--- a/fastboot/device/utility.cpp
+++ b/fastboot/device/utility.cpp
@@ -36,7 +36,6 @@
 using namespace android::fs_mgr;
 using namespace std::chrono_literals;
 using android::base::unique_fd;
-using android::hardware::boot::V1_0::Slot;
 
 namespace {
 
@@ -137,7 +136,7 @@
     return true;
 }
 
-bool GetSlotNumber(const std::string& slot, Slot* number) {
+bool GetSlotNumber(const std::string& slot, int32_t* number) {
     if (slot.size() != 1) {
         return false;
     }
@@ -204,7 +203,7 @@
     size_t num_slots = 1;
     auto boot_control_hal = device->boot_control_hal();
     if (boot_control_hal) {
-        num_slots = boot_control_hal->getNumberSlots();
+        num_slots = boot_control_hal->GetNumSlots();
     }
 
     bool ok = true;