Remove duplicate customize_install function (#540)

Fix a couple minor typos while we're at it

get-poetry.py

@@ -412,7 +412,7 @@ class Installer:
     def customize_install(self):
         if not self._accept_all:
             print("Before we start, please answer the following questions.")
-            print("You may simple press the Enter key to keave unchanged.")
+            print("You may simply press the Enter key to leave unchanged.")
 
             modify_path = input("Modify PATH variable? ([y]/n) ") or "y"
             if modify_path.lower() in {"n", "no"}:
@@ -434,17 +434,6 @@ class Installer:
 
         return True
 
-    def customize_install(self):
-        if not self._accept_all:
-            print("Before we start, please answer the following questions.")
-            print("You may simple press the Enter key to keave unchanged.")
-
-            modify_path = input("Modify PATH variable? ([y]/n) ") or "y"
-            if modify_path.lower() in {"n", "no"}:
-                self._modify_path = False
-
-            print("")
-
     def ensure_home(self):
         """
         Ensures that $POETRY_HOME exists or create it.