Revert "[Basic] Limit version::getCompilerversion to major + minor only"

This reverts commit 17af078.

Author: xedin

lib/Basic/Version.cpp

@@ -343,10 +343,11 @@ std::string getCompilerVersion() {
   std::string buf;
   llvm::raw_string_ostream OS(buf);
 
- // TODO: This should print SWIFT_COMPILER_VERSION when
- // available, but to do that we need to switch from
- // llvm::VersionTuple to swift::Version.
- OS << SWIFT_VERSION_STRING;
+#if defined(SWIFT_COMPILER_VERSION)
+  OS << SWIFT_COMPILER_VERSION;
+#else
+  OS << SWIFT_VERSION_STRING;
+#endif
 
   return OS.str();
 }