Fix google-explicit-constructor warnings.

Bug: 28341362
Change-Id: I625fbab25f16282c2ea929cd16283d9d146fa17b
diff --git a/camera/ICameraClient.cpp b/camera/ICameraClient.cpp
index 179a341..bda122d 100644
--- a/camera/ICameraClient.cpp
+++ b/camera/ICameraClient.cpp
@@ -33,7 +33,7 @@
 class BpCameraClient: public BpInterface<ICameraClient>
 {
 public:
-    BpCameraClient(const sp<IBinder>& impl)
+    explicit BpCameraClient(const sp<IBinder>& impl)
         : BpInterface<ICameraClient>(impl)
     {
     }