apexd: slightly improve logging in mountNonFlattened

* Log failure for all the retries.
* Cache errno of last mount attempt to make it possible to propagate it
  to the failure message. Currently, when last mount attempt fails,
  apexd still calls usleep(50000), which AFAIU zeroes out errno.

Test: builds
Change-Id: I5b40933ecae54b45ea60967ceeb03143a0e095ba
1 file changed
tree: 79d60d61517238a278d35a0c03ba11f9c4f5f487
  1. apexd/
  2. apexer/
  3. proto/
  4. tests/
  5. OWNERS
  6. PREUPLOAD.cfg
  7. TEST_MAPPING