base: rename unique_fd::clear() to unique_fd::reset().

unique_fd is modeled on unique_ptr, so make this consistent.

Test: m checkbuild
Change-Id: Ia6a77095dc18746fbb432e96bb8dccfc049c57f6
diff --git a/include/android-base/unique_fd.h b/include/android-base/unique_fd.h
index c323311..6cfcfcd 100644
--- a/include/android-base/unique_fd.h
+++ b/include/android-base/unique_fd.h
@@ -55,7 +55,7 @@
   unique_fd_impl() : value_(-1) {}
 
   explicit unique_fd_impl(int value) : value_(value) {}
-  ~unique_fd_impl() { clear(); }
+  ~unique_fd_impl() { reset(); }
 
   unique_fd_impl(unique_fd_impl&& other) : value_(other.release()) {}
   unique_fd_impl& operator=(unique_fd_impl&& s) {
@@ -63,17 +63,13 @@
     return *this;
   }
 
-  void reset(int new_value) {
+  void reset(int new_value = -1) {
     if (value_ != -1) {
       Closer::Close(value_);
     }
     value_ = new_value;
   }
 
-  void clear() {
-    reset(-1);
-  }
-
   int get() const { return value_; }
   operator int() const { return get(); }