ENH: use GLM starting values for QIF

[kshedden]

No description provided.

[coveralls]

Coverage decreased (-0.03%) to 87.569% when pulling 83522a4 on kshedden:qif_start into 033d56d on statsmodels:master.

[codecov]

Codecov Report

Merging #6514 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #6514      +/-   ##
==========================================
+ Coverage   85.22%   85.22%   +<.01%     
==========================================
  Files         643      643              
  Lines      103160   103163       +3     
  Branches    11234    11234              
==========================================
+ Hits        87914    87917       +3     
  Misses      12798    12798              
  Partials     2448     2448

Impacted Files	Coverage Δ
statsmodels/genmod/qif.py	81.36% <100%> (+0.25%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 033d56d...83522a4. Read the comment docs.