abi: extract_symbols: handle empty lines in whitelist files

Empty lines in existing whitelist files are confusing the symbol sort
mechanism, hence ignore them and return what we got.
Also ignore these empty lines as they are no good anyways.

Bug: 146985684
Change-Id: I6a0101b425d5e7c47515a64fbddf742e7ef3806c
Signed-off-by: Matthias Maennich <maennich@google.com>
1 file changed