EPEL7 "Requires:" is sometime wrong

A trouble with EPEL7 is the requirement (`Requires:`) syntax.

**pyp2rpm** uses syntax like `python3-`, which is sometimes incorrect. For instance, many packages start with capital letter and EPEL7 downcases them (for instance see at package named `Flask`).

I feel fine with `%{?python_enable_dependency_generator}`, it works well with el8. But it doesn't work with el7 (at least some versions of el7, even with latest rpm macros installed).

`%{?python_enable_dependency_generator}` add requirements in the following form

`python3.6dist(flask)`

which is EPEL7 compatible. Instead, `python3-Flask` or `python3dist(flask)` are not compatible with EPEL7.