build-all: Don't mention a nonexistent --with-python option

This was added in 050b4ef, but
such an option never existed in build-all.sh, only in
build-cross-tools.sh.

Author: mstorsjo

build-all.sh

@@ -87,7 +87,7 @@ while [ $# -gt 0 ]; do
     shift
 done
 if [ -z "$PREFIX" ]; then
-    echo "$0 [--host-clang[=clang]] [--enable-asserts] [--disable-dylib] [--full-llvm] [--with-python] [--disable-lldb] [--disable-lldb-mi] [--disable-clang-tools-extra] [--host=triple] [--with-default-win32-winnt=0x601] [--with-default-msvcrt=ucrt] [--enable-cfguard|--disable-cfguard] [--no-runtimes] [--no-tools] [--wipe-runtimes] [--clean-runtimes] dest"
+    echo "$0 [--host-clang[=clang]] [--enable-asserts] [--disable-dylib] [--full-llvm] [--disable-lldb] [--disable-lldb-mi] [--disable-clang-tools-extra] [--host=triple] [--with-default-win32-winnt=0x601] [--with-default-msvcrt=ucrt] [--enable-cfguard|--disable-cfguard] [--no-runtimes] [--no-tools] [--wipe-runtimes] [--clean-runtimes] dest"
     exit 1
 fi