support install from venv and travis CI

Makefile

@@ -4,9 +4,6 @@ EXAMPLES_PATH ?= ${HOME}/nni/examples
 WHOAMI := $(shell whoami)
 YARN := $(INSTALL_PREFIX)/yarn/bin/yarn
 PIP_MODE ?= --user
-ifdef TRAVIS
-undefine PIP_MODE
-endif
 ifdef VIRTUAL_ENV
 undefine PIP_MODE
 endif

test/naive/run.py

@@ -76,10 +76,10 @@ if __name__ == '__main__':
         run()
         # TODO: check the output of rest server
         print(GREEN + 'PASS' + CLEAR)
-    except Exception as e:
+    except Exception as error:
         print(RED + 'FAIL' + CLEAR)
-        print('%r' % e)
+        print('%r' % error)
         traceback.print_exc()
-        raise e
+        raise error
 
     subprocess.run(['nnictl', 'stop'])