[ELF] - Versionscript: do not treat non-wildcarded names as wildcards.

Previously we incorrectly handled cases when symbol name in extern c++ tag
was enclosed in quotes. Next case was treated as wildcard:

GLIBCXX_3.4 {                                                                   
    extern "C++" {  
    "aaa*"
   }
But it should have not. Quotes around aaa here means that we should have do exact
name matching.
That is PR30268 which has name with pointer is interpreted as wildcard by lld:

extern "C++" {                                                              
    "operator delete[](void*)";

Patch fixes the issue.

Differential revision: https://reviews.llvm.org/D24229

llvm-svn: 281038