TST fix file descriptor leak and a bad variable name in get_testlog

scrapy/utils/test.py

@@ -53,11 +53,13 @@ def get_testenv():
 
 def get_testlog():
     """Get Scrapy log of current test, ignoring the rest"""
+    with open("test.log", "rb") as fp:
+        loglines = fp.readlines()
+
     thistest = []
-    loglines = open("test.log").readlines()
-    for l in loglines[::-1]:
-        thistest.append(l)
-        if "[-] -->" in l:
+    for line in loglines[::-1]:
+        thistest.append(line)
+        if "[-] -->" in line:
             break
     return "".join(thistest[::-1])