Deprecates utils.create_dir().

This function was a workaround for the exist_ok flag missing
from Python3.4. Now that Python3.4 is past the final release,
we no longer need to support that version.

Also fixes UTs broken by aosp/1231574.

Bug: None
Test: UTs.
Change-Id: If0592017e1bf374d6b4f5d27c17c32276979029a
diff --git a/acts/framework/acts/test_utils/wifi/wifi_test_utils.py b/acts/framework/acts/test_utils/wifi/wifi_test_utils.py
index 8f356ed..9f4a91b 100755
--- a/acts/framework/acts/test_utils/wifi/wifi_test_utils.py
+++ b/acts/framework/acts/test_utils/wifi/wifi_test_utils.py
@@ -2103,7 +2103,7 @@
         ad.log.info("Pulling ssrdumps %s", logs)
         log_path = os.path.join(ad.log_path, test_name,
                                 "SSRDUMP_%s" % ad.serial)
-        utils.create_dir(log_path)
+        os.makedirs(log_path, exist_ok=True)
         ad.pull_files(logs, log_path)
     ad.adb.shell("find /data/vendor/ssrdump/ -type f -delete")
 
@@ -2121,7 +2121,7 @@
     """
     log_dir = os.path.join(
         context.get_current_context().get_full_output_path(), 'PacketCapture')
-    utils.create_dir(log_dir)
+    os.makedirs(log_dir, exist_ok=True)
     if wifi_band == 'dual':
         bands = [BAND_2G, BAND_5G]
     else:
@@ -2224,7 +2224,7 @@
     if logs:
         ad.log.info("Pulling cnss_diag logs %s", logs)
         log_path = os.path.join(ad.device_log_path, "CNSS_DIAG_%s" % ad.serial)
-        utils.create_dir(log_path)
+        os.makedirs(log_path, exist_ok=True)
         ad.pull_files(logs, log_path)