Cleaned up some slot logic

Doesn't look like we actually need current_slot, since we can always
just call function get_current_slot

Test: tested flashall on raven
Change-Id: Icba64bc9fdd08f36d44965e32558a73d0beab0e1
diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index 42269fe..b977e31 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -1560,10 +1560,10 @@
     }
 }
 
-std::string GetPartitionName(const ImageEntry& entry, std::string& current_slot) {
+std::string GetPartitionName(const ImageEntry& entry) {
     auto slot = entry.second;
     if (slot.empty()) {
-        slot = current_slot;
+        slot = get_current_slot();
     }
     if (slot.empty()) {
         return entry.first->part_name;
@@ -1582,7 +1582,7 @@
 
   private:
     void CheckRequirements();
-    void DetermineSlot();
+    void DetermineSecondarySlot();
     void CollectImages();
     void FlashImages(const std::vector<std::pair<const Image*, std::string>>& images);
     void FlashImage(const Image& image, const std::string& slot, fastboot_buffer* buf);
@@ -1600,15 +1600,13 @@
 
     // Change the slot first, so we boot into the correct recovery image when
     // using fastbootd.
-    if (fp_->slot == "all") {
+    if (fp_->slot_override == "all") {
         set_active("a");
     } else {
-        set_active(fp_->slot);
+        set_active(fp_->slot_override);
     }
 
-    DetermineSlot();
-    CollectImages();
-
+    DetermineSecondarySlot();
     CancelSnapshotIfNeeded();
 
     // First flash boot partitions. We allow this to happen either in userspace
@@ -1653,18 +1651,12 @@
     ::CheckRequirements({contents.data(), contents.size()}, fp_->force_flash);
 }
 
-void FlashAllTool::DetermineSlot() {
-    if (fp_->slot.empty()) {
-        fp_->current_slot = get_current_slot();
-    } else {
-        fp_->current_slot = fp_->slot;
-    }
-
+void FlashAllTool::DetermineSecondarySlot() {
     if (fp_->skip_secondary) {
         return;
     }
-    if (fp_->slot != "" && fp_->slot != "all") {
-        fp_->secondary_slot = get_other_slot(fp_->slot);
+    if (fp_->slot_override != "" && fp_->slot_override != "all") {
+        fp_->secondary_slot = get_other_slot(fp_->slot_override);
     } else {
         fp_->secondary_slot = get_other_slot();
     }
@@ -1678,7 +1670,7 @@
 
 void FlashAllTool::CollectImages() {
     for (size_t i = 0; i < images.size(); ++i) {
-        std::string slot = fp_->slot;
+        std::string slot = fp_->slot_override;
         if (images[i].IsSecondary()) {
             if (fp_->skip_secondary) {
                 continue;