Remove catch + sys.exit idiom

This is bad, python already prints exceptino message and exit with
non-zero code when an exception is raised, no need to catch the
exception just to print it. In addition, printing an exception does not
print stacktrace, so catch + sys.exit provide less information than
python's default behavior.

Test: th
Change-Id: If6cf2e34d4ebc9f7d172063b4396bf4377dad447

tools/releasetools/check_ota_package_signature.py

@@ -181,8 +181,5 @@ def main():
 if __name__ == '__main__':
   try:
     main()
-  except AssertionError as err:
-    print('\n    ERROR: %s\n' % (err,))
-    sys.exit(1)
   finally:
     common.Cleanup()

tools/releasetools/check_partition_sizes.py

@@ -300,8 +300,5 @@ if __name__ == "__main__":
   try:
     common.CloseInheritedPipes()
     main(sys.argv[1:])
-  except common.ExternalError:
-    logger.exception("\n   ERROR:\n")
-    sys.exit(1)
   finally:
     common.Cleanup()

tools/releasetools/check_target_files_vintf.py

@@ -286,8 +286,5 @@ if __name__ == '__main__':
   try:
     common.CloseInheritedPipes()
     main(sys.argv[1:])
-  except common.ExternalError:
-    logger.exception('\n   ERROR:\n')
-    sys.exit(1)
   finally:
     common.Cleanup()

tools/releasetools/img_from_target_files.py

@@ -251,8 +251,5 @@ if __name__ == '__main__':
   try:
     common.CloseInheritedPipes()
     main(sys.argv[1:])
-  except common.ExternalError as e:
-    logger.exception('\n   ERROR:\n')
-    sys.exit(1)
   finally:
     common.Cleanup()

tools/releasetools/sign_apex.py

@@ -149,8 +149,5 @@ def main(argv):
 if __name__ == '__main__':
   try:
     main(sys.argv[1:])
-  except common.ExternalError:
-    logger.exception("\n   ERROR:\n")
-    sys.exit(1)
   finally:
     common.Cleanup()