Remove all BUCK files

ReactAndroid/src/main/java/com/facebook/soloader/BUCK

@@ -1,20 +0,0 @@
-include_defs('//ReactAndroid/DEFS')
-
-android_library(
-  name = 'soloader',
-  srcs = glob(['*.java']),
-  proguard_config = 'soloader.pro',
-  deps = [
-    react_native_dep('third-party/java/jsr-305:jsr-305'),
-    # Be very careful adding new dependencies here, because this code
-    # has to run very early in the app startup process.
-    # Definitely do *not* depend on lib-base or guava.
-  ],
-  visibility = [
-    'PUBLIC',
-  ],
-)
-
-project_config(
-  src_target = ':soloader',
-)