Renaming a overloaded function should rename only the function with the same signature

...or ask at least if it's ok to rename all occurences.

Steps to reproduce:

• open tests/manual/cplusplus-tools/cplusplus-tools.pro
• open source.cpp, place cursor onto one of the freefunc2() functions
• invoke Rename Symbol Under Cursor

Expected behaviour:

• Creator should only rename functions with exactly the same signature
  OR
• Creator should ask if renaming should be done on all (including overloaded) functions or only for functions with matching signature

Current behaviour:

• Creator renames all occurences of this function - no matter if it's the same signature or not