target_link_libraries: Revert accidental change

In commit c4373b33 (cmTarget: Make GetProperty() const, 2013-10-29)
we accidentally changed the cmTargetLinkLibrariesCommand.cxx logic
in a way that looks like a local experiment leftover that went
unnoticed due to the size of the other changes in the commit.
Revert it.

Source/cmTargetLinkLibrariesCommand.cxx

@@ -384,13 +384,8 @@ cmTargetLinkLibrariesCommand::HandleLibrary(const char* lib,
         }
     }
 
-  if(this->CurrentProcessingState == ProcessingLinkLibraries
+  // Handle normal case first.
-        && !this->Target->GetProperty("LINK_INTERFACE_LIBRARIES"))
+  if(this->CurrentProcessingState != ProcessingKeywordLinkInterface
-    {
-    this->Makefile
-      ->AddLinkLibraryForTarget(this->Target->GetName(), lib, llt);
-    }
-  else if(this->CurrentProcessingState != ProcessingKeywordLinkInterface
       && this->CurrentProcessingState != ProcessingPlainLinkInterface)
     {
     this->Makefile