[sanitizer] Simplify few lines in bot script
diff --git a/zorg/buildbot/builders/sanitizers/buildbot_android_functions.sh b/zorg/buildbot/builders/sanitizers/buildbot_android_functions.sh
index a2ba535..341a05b 100755
--- a/zorg/buildbot/builders/sanitizers/buildbot_android_functions.sh
+++ b/zorg/buildbot/builders/sanitizers/buildbot_android_functions.sh
@@ -72,9 +72,8 @@
   # Always clobber android build tree.
   # It has a hidden dependency on clang (through CXX) which is not known to
   # the build system.
-  rm -rf compiler_rt_build_android_$_arch
+  rm_dirs compiler_rt_build_android_$_arch llvm_build_android_$_arch
   mkdir -p compiler_rt_build_android_$_arch
-  rm -rf llvm_build_android_$_arch
   mkdir -p llvm_build_android_$_arch
 
   (cd llvm_build_android_$_arch && cmake \