linker: remove unnecessary reset of constructors_called flag

linker doesn't call d-tors for RTLD_NODELETE libraries. There is
no need in reseting this flag in call_destructors (which is called
from soinfo_unload).

Change-Id: I3ed03fa7207b7acf598067276fbb8874e29b5e53
diff --git a/linker/linker.cpp b/linker/linker.cpp
index bda713e..f3370ec 100644
--- a/linker/linker.cpp
+++ b/linker/linker.cpp
@@ -3023,10 +3023,6 @@
   // DT_FINI should be called after DT_FINI_ARRAY if both are present.
   call_function("DT_FINI", fini_func_);
-  // This is needed on second call to dlopen
-  // after library has been unloaded with RTLD_NODELETE
-  constructors_called = false;
 void soinfo::add_child(soinfo* child) {