Fix for elliptic curve L-function plots

Elliptic curve L-function plots were broken for large conductor because
I had previously "optimized" plotting by precomputing the plot data. The
database I created with a larger number of plots had a slightly
different format than the small database I had created.

The database on the server will need to be switched to the larger one
before plots actually appear, but the code should work with either the
small database or the large one.
Merge branch 'master' of github.com:LMFDB/lmfdb
Merge branch 'master' of github.com:LMFDB/lmfdb