Improve error message for GetMinSdkVersion

Bug: 219148978
Test: th
Change-Id: I72c653b6e7e159abf0b7aca394cf465869542483
diff --git a/tools/releasetools/common.py b/tools/releasetools/common.py
index 8506199..f4f9178 100644
--- a/tools/releasetools/common.py
+++ b/tools/releasetools/common.py
@@ -2244,8 +2244,8 @@
   stdoutdata, stderrdata = proc.communicate()
   if proc.returncode != 0:
     raise ExternalError(
-        "Failed to obtain minSdkVersion: aapt2 return code {}:\n{}\n{}".format(
-            proc.returncode, stdoutdata, stderrdata))
+        "Failed to obtain minSdkVersion for {}: aapt2 return code {}:\n{}\n{}".format(
+            apk_name, proc.returncode, stdoutdata, stderrdata))
 
   for line in stdoutdata.split("\n"):
     # Looking for lines such as sdkVersion:'23' or sdkVersion:'M'.