Switch to aapt2 for getting minSdkVersion

aapt does not support parsing some referencing attributes.
Switch to latest tool, aapt2, which works better.

Test: aapt2 dump badging test.apk and returned 0.
Test: Run check_target_files_signatures.py with a target_files.zip.
Test: Run sign_target_files_apks.py with a target_files.zip.
Change-Id: Ib3a4740506f29ebab6930767f2aa8a0b5c4ba053
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 913601f..0594b79 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -1048,7 +1048,7 @@
 def GetMinSdkVersion(apk_name):
   """Gets the minSdkVersion declared in the APK.
 
-  It calls 'aapt' to query the embedded minSdkVersion from the given APK file.
+  It calls 'aapt2' to query the embedded minSdkVersion from the given APK file.
   This can be both a decimal number (API Level) or a codename.
 
   Args:
@@ -1061,12 +1061,12 @@
     ExternalError: On failing to obtain the min SDK version.
   """
   proc = Run(
-      ["aapt", "dump", "badging", apk_name], stdout=subprocess.PIPE,
+      ["aapt2", "dump", "badging", apk_name], stdout=subprocess.PIPE,
       stderr=subprocess.PIPE)
   stdoutdata, stderrdata = proc.communicate()
   if proc.returncode != 0:
     raise ExternalError(
-        "Failed to obtain minSdkVersion: aapt return code {}:\n{}\n{}".format(
+        "Failed to obtain minSdkVersion: aapt2 return code {}:\n{}\n{}".format(
             proc.returncode, stdoutdata, stderrdata))
 
   for line in stdoutdata.split("\n"):
@@ -1074,7 +1074,7 @@
     m = re.match(r'sdkVersion:\'([^\']*)\'', line)
     if m:
       return m.group(1)
-  raise ExternalError("No minSdkVersion returned by aapt")
+  raise ExternalError("No minSdkVersion returned by aapt2")
 
 
 def GetMinSdkVersionInt(apk_name, codename_to_api_level_map):