[libclang/python] Remove compatibility workaround for briefComment (#138135)

Remove a workaround that made cindex.py from LLVM 3.2 work with older
libclang.so versions

Author: DeinAlptraum

clang/bindings/python/clang/cindex.py

@@ -2980,11 +2980,7 @@ def availability(self):
 
     @property
     def briefComment(self):
-        if conf.function_exists("clang_getCompletionBriefComment"):
-            return _CXString.from_result(
-                conf.lib.clang_getCompletionBriefComment(self.obj)
-            )
-        return ""
+        return _CXString.from_result(conf.lib.clang_getCompletionBriefComment(self.obj))
 
     def __repr__(self):
         return (
@@ -4264,14 +4260,6 @@ def get_cindex_library(self) -> CDLL:
 
         return library
 
-    def function_exists(self, name: str) -> bool:
-        try:
-            getattr(self.lib, name)
-        except AttributeError:
-            return False
-
-        return True
-
 
 conf = Config()