client: fix script execution

if __name__ == "__main__" should be first instead of try block. We want
execute it only when file was executed as script

https://fedorahosted.org/freeipa/ticket/6392

Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>

client/ipa-client-install

@@ -257,15 +257,16 @@ def main():
 
     return rval
 
-try:
-    if __name__ == "__main__":
-        sys.exit(main())
-except KeyboardInterrupt:
-    sys.exit(1)
-except RuntimeError as e:
-    sys.exit(e)
-finally:
+
+if __name__ == "__main__":
     try:
-        os.remove(client.CCACHE_FILE)
-    except Exception:
-        pass
+        sys.exit(main())
+    except KeyboardInterrupt:
+        sys.exit(1)
+    except RuntimeError as e:
+        sys.exit(e)
+    finally:
+        try:
+            os.remove(client.CCACHE_FILE)
+        except Exception:
+            pass