Revert an unnecessary change in //build/compiler_version.py.

The script doesn't seem to be in use anymore, and in fact the change
will break assembler version detection.

build/compiler_version.py

@@ -54,7 +54,7 @@ def GetVersion(compiler, tool):
   try:
     # Note that compiler could be something tricky like "distcc g++".
     if tool == "assembler":
-      compiler = compiler + " --version -Xassembler -x assembler -c /dev/null"
+      compiler = compiler + " -Xassembler --version -x assembler -c /dev/null"
       # Unmodified: GNU assembler (GNU Binutils) 2.24
       # Ubuntu: GNU assembler (GNU Binutils for Ubuntu) 2.22
       # Fedora: GNU assembler version 2.23.2