VS10: Use $(IntDir) for per-source output directory (#11270)

The original implementation of this generator accidentally used
"$(Configuration)/" for source-specific object file names.  Correct it
to use "$(IntDir)/" just like the generators for all previous VS
versions.  The target-wide output directory is "$(IntDir)/" already.

Source/cmVisualStudio10TargetGenerator.cxx

@@ -767,7 +767,7 @@ bool cmVisualStudio10TargetGenerator::OutputSourceSpecificFlags(
     hasFlags = true;
     this->WriteString("<ObjectFileName>", 3);
     (*this->BuildFileStream )
-      << "$(Configuration)/" << objectName << "</ObjectFileName>\n";
+      << "$(IntDir)/" << objectName << "</ObjectFileName>\n";
     }
   std::vector<std::string> *configs =
     static_cast<cmGlobalVisualStudio7Generator *>