Fix build wheels testing: don't install [test]

Don't run `pip install asyncpg[test]` to test wheels; the [test]
deps only include flake8 & uvloop. The former isn't necessary; the
latter doesn't work on manylinux1.

Author: 1st1

.ci/build-manylinux-wheels.sh

@@ -16,7 +16,7 @@ for whl in /io/dist/*.whl; do
     rm /io/dist/*-linux_*.whl
 done
 
-${PIP} install ${PYMODULE}[test] -f "file:///io/dist"
+${PIP} install ${PYMODULE} -f "file:///io/dist"
 
 # Grab docker host, where Postgres should be running.
 export PGHOST=$(ip route | awk '/default/ { print $3 }' | uniq)

.ci/travis-build-wheels.sh

@@ -66,7 +66,7 @@ elif [ "${TRAVIS_OS_NAME}" == "osx" ]; then
     make clean
     python setup.py bdist_wheel
 
-    pip install ${PYMODULE}[test] -f "file:///${_root}/dist"
+    pip install ${PYMODULE} -f "file:///${_root}/dist"
     make -C "${_root}" ASYNCPG_VERSION="${PACKAGE_VERSION}" testinstalled
 
     _upload_wheels