Drop obsolete -laws-cpp-sdk-s3

Dependencies

• [2] GTUZLZRH Add an S3-backed binary cache store
• [3] 73YR46NJ hydra-queue-runner: Write directly to a binary cache
• [4] KS7NNPQW Bleh Automake
• [5] 7VQ4ALFY Update "make check" for the new queue runner
• [6] 24BMQDZA Start of single-process hydra-queue-runner
• [7] 3YSJ3LYK Remove finally.hh
• [8] V6H6BWMK Sync with Nix
• [9] N4IROACV Move buildRemote() into State
• [10] N2NKSKHS Refactor local binary cache code into a subclass
• [11] MHVIT4JY Split hydra-queue-runner.cc more
• [12] GH4S4AWM Rename file
• [13] HJOEIMLR Refactor
• [14] 5AIYUMTB Basic remote building
• [15] FS3HUMVU Fix Makefile.am

Change contents

• replacement in src/hydra-queue-runner/Makefile.am at line 8
  [3.369]→[2.230:281](∅→∅)
  − AM_CXXFLAGS = $(NIX_CFLAGS) -Wall -laws-cpp-sdk-s3
  [3.369]
  + AM_CXXFLAGS = $(NIX_CFLAGS) -Wall