depends_on :python don't set any LDFLAGS

Setting LDFLAGS to `-F HOMEBREW_PREFIX/opt/python/Frameworks`
breaks at least the scipy build. Perhaps others, too.

Library/Homebrew/python_helper.rb

@@ -64,7 +64,6 @@ def python_helper(options={:allowed_major_versions => [2, 3]}, &block)
           ENV.prepend 'CMAKE_INCLUDE_PATH', py.incdir, ':'
           ENV.prepend 'PKG_CONFIG_PATH', py.pkg_config_path, ':' if py.pkg_config_path
           ENV.prepend 'PATH', py.binary.dirname, ':' unless py.from_osx?
-          ENV.prepend 'LDFLAGS', "-F#{py.framework}" if py.brewed?
           # Track the state of the currently selected python for this block,
           # so if this python_helper is called again _inside_ the block,
           # we can just return the right python (see `else`-branch a few lines down):