Strip LLVM svn rev from `llvm-config --version` output.

Reviewed-by: Vinson Lee <vlee@freedesktop.org>

configure.ac

@@ -1773,7 +1773,7 @@ if test "x$enable_gallium_llvm" = xyes; then
     AC_PATH_PROG([LLVM_CONFIG], [llvm-config], [no])
 
     if test "x$LLVM_CONFIG" != xno; then
-	LLVM_VERSION=`$LLVM_CONFIG --version`
+	LLVM_VERSION=`$LLVM_CONFIG --version | sed 's/svn.*//g'`
 	LLVM_CFLAGS=`$LLVM_CONFIG --cppflags|sed -e 's/-DNDEBUG\>//g' -e 's/-pedantic//g'`
 	LLVM_LIBS="`$LLVM_CONFIG --libs`"