Need to modify gr-osmosdr.rb to satisfy audit problems generated by "brew audit --strict --online gr-osmosdr"

[chleggett]

% brew audit --strict --online gr-osmosdr ==> brew style gr-osmosdr

1 file inspected, no offenses detected

==> audit problems chleggett/gr-osmosdr/gr-osmosdr:

• Stable: SHA1 checksums are deprecated, please use SHA256
• Formula should have a desc (Description).
• require "formula" is now unnecessary
• python modules have explicit framework links These python extension modules were linked directly to a Python framework binary. They should be linked with -undefined dynamic_lookup instead of -lpython or -framework Python. /usr/local/Cellar/gr-osmosdr/0.1.4/lib/python2.7/site-packages/osmosdr/_osmosdr_swig.so

Error: 4 problems in 1 formula

[chleggett]

The python modules bullet was satisfied by e5aaaca.

However, that commit also introduced some style problems.

I am going to open a separate issue for those.