Remove signed field from commits

[josecordaz]

• First draft to remove signed field from commits. It is not being used.

[xzandrew]

This has compile errors in tests:

go test github.com/pinpt/ripsrc/...
# github.com/pinpt/ripsrc/ripsrc/commitmeta/tests [github.com/pinpt/ripsrc/ripsrc/commitmeta/tes
ts.test]
ripsrc/commitmeta/tests/basic_test.go:46:3: unknown field 'Signed' in struct literal of type com
mitmeta.Commit
ripsrc/commitmeta/tests/basic_test.go:62:3: unknown field 'Signed' in struct literal of type com
mitmeta.Commit
ripsrc/commitmeta/tests/merge_basic_test.go:35:3: unknown field 'Signed' in struct literal of ty
pe commitmeta.Commit
ripsrc/commitmeta/tests/merge_basic_test.go:59:3: unknown field 'Signed' in struct literal of ty
pe commitmeta.Commit
ripsrc/commitmeta/tests/merge_basic_test.go:83:3: unknown field 'Signed' in struct literal of ty
pe commitmeta.Commit
ripsrc/commitmeta/tests/merge_basic_test.go:107:3: unknown field 'Signed' in struct literal of t
ype commitmeta.Commit```

[rblalock]

Here is an overview of what got changed by this pull request:

Complexity decreasing per file
==============================
+ ripsrc/commitmeta/commitmeta.go  -2

See the complete overview on Codacy