Revert "set max open db connections to 64"
Revert "set max open db connections to 64"

some folks are hitting this limit and ATC gets wedged. we should
characterize the connection count first.

This reverts commit 6447591239386ddee3a2b429eec6dd7de57fc20e.

zachgersh/atc,zachgersh/atc,zachgersh/atc,zachgersh/atc