argument: Fix flag typo

Change-Id: I409db7d3e8042217312225ac642b312541c48981
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/argument.cpp b/argument.cpp
index 61c97ca..ee66e37 100644
--- a/argument.cpp
+++ b/argument.cpp
@@ -31,7 +31,7 @@
 const char* ArgumentParser::optionStr = "p:s:t:c:?h";
 const option ArgumentParser::options[] =
 {
-    { "path",     required_argument,  nullptr,   'o' },
+    { "path",     required_argument,  nullptr,   'p' },
     { "service",  required_argument,  nullptr,   's' },
     { "target",   required_argument,  nullptr,   't' },
     { "continue", no_argument,        nullptr,   'c' },