Fix test error "fatal: empty ident name (for <(null)>) not allowed"

Occurs when tests run with tox not with Travis CI or Appveyor

Changed existing tox setenv statement to use whitespace around `=` as per
http://tox.readthedocs.io/en/latest/example/basic.html#setting-environment-variables

tox.ini

@@ -6,7 +6,12 @@ envlist = py27,py34,py35,pypy
 [testenv]
 deps = -rrequirements-dev.txt
 passenv = HOME HOMEPATH PROGRAMDATA TERM
-setenv = VIRTUALENV_NO_DOWNLOAD=1
+setenv =
+    VIRTUALENV_NO_DOWNLOAD = 1
+    GIT_AUTHOR_NAME = "test"
+    GIT_COMMITTER_NAME = "test"
+    GIT_AUTHOR_EMAIL = "test@example.com"
+    GIT_COMMITTER_EMAIL = "test@example.com"
 commands =
     coverage erase
     coverage run -m pytest {posargs:tests}