database/sql: remove unnecessary else conditions
database/sql: remove unnecessary else conditions

Fixes golint warning about "if block ends with a return statement,
so drop this else and outdent its block".

Change-Id: Iac4fd324e04e3e3fe3e3933f5e59095041d292c5
Reviewed-on: https://go-review.googlesource.com/107115
Reviewed-by: Daniel Martí <29bf28b42a938ace12a5819da4ed4ba03d82f315@mvdan.cc>
Reviewed-by: Daniel Theophanes <14db39248b80c6688f7e9808ba5055f2e56426f3@gmail.com>
Run-TryBot: Daniel Martí <29bf28b42a938ace12a5819da4ed4ba03d82f315@mvdan.cc>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>

cloudflare/go,cloudflare/go,nawawi/go,nawawi/go,josharian/go,akutz/go,josharian/go,akutz/go,akutz/go,nawawi/go,nawawi/go,cloudflare/go,golang/go,golang/go,CAFxX/go,nawawi/go,CAFxX/go,josharian/go,golang/go,CAFxX/go,CAFxX/go,CAFxX/go,cloudflare/go,nawawi/go,josharian/go,golang/go,nawawi/go,CAFxX/go,golang/go,golang/go,CAFxX/go,akutz/go,golang/go,akutz/go,josharian/go,cloudflare/go,akutz/go,josharian/go,josharian/go,josharian/go,akutz/go,nawawi/go,CAFxX/go,cloudflare/go,cloudflare/go,cloudflare/go,akutz/go,golang/go