This commit removes completely the src/.gitignore file, given that the
precedent for ignoring artifacts within the `src` directory is to
add entries for them to the root .gitignore file.
Note also that the lone entry in src/.gitignore is stale anyway. As of
the switch to Autotools in 35b8af9, the build no longer build creates
artifacts in `src/test_bitcoin`. They are now written to
`src/test/test_bitcoin`, and this latter path is already ignored in the
root .gitignore file.
Prior to this change, `git status` would report untracked files of the
following sort if run during a build:
?? src/rpcprotocol.o-e628def3
These files should be explicitly ignored not only because they are a
nuisance, but given that they appear and disappear quickly, they may be
inadvertently added to the index even if one has been careful to check
for untracked files with `git status` prior to a `git add .`.
Chris Beams