The last 4 bytes of a GZIP file is the decompressed file length, and
are used in eboot to do sanity checks and know when decompression is
done.

Updater was incorrectly telling eboot to look at
"end-of-bin + sizeof(signing)", and when eboot did so it got an
incorrect value causing either the update to be skipped or for only a
portion of update to be completed.

Fix by adjusting the size back to the end of binary.
Fixes esp8266#7570

* master: (299 commits)
  Fix error message typo (esp8266#7581)
  Update certs-from-mozilla.py (esp8266#7578)
  Update DigestAuthorization.ino (Simple example update) (esp8266#7579)
  Fix gzip+signed OTA error (esp8266#7577)
  Properly replace toolchain in PlatformIO CI script (esp8266#7580)
  Update certs-from-mozilla.py (esp8266#7573)
  Fixup weird combination of oneline/multi line comments (esp8266#7566)
  Reduce codesize of setOutputPower (esp8266#7572)
  Fix typos in tests
  Force gcc inlining, use same style for getCycleCount as for getCpuFreqMHz.
  Even more concise #if form.
  Inline, fewer LOC, remove redundant definition in cpp.
  Netump Initial commit (esp8266#7527)
  Delete owner field (esp8266#7563)
  Avoid float-double-conversion (esp8266#7559)
  Use direct member initialization instead of ctr initialisation (esp8266#7556)
  Add CI test for eboot build (esp8266#7546)
  getCpuFreqMHz(): fix when F_CPU is not defined (esp8266#7554)
  emulation-on-host makefile update, allowing to pass more options (esp8266#7552)
  add sdk options to "generic esp8285 module" (esp8266#7550)
  ...

The last 4 bytes of a GZIP file is the decompressed file length, and
are used in eboot to do sanity checks and know when decompression is
done.

Updater was incorrectly telling eboot to look at
"end-of-bin + sizeof(signing)", and when eboot did so it got an
incorrect value causing either the update to be skipped or for only a
portion of update to be completed.

Fix by adjusting the size back to the end of binary.
Fixes esp8266#7570