Update manual pages

doc/h2load.1

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-.TH "H2LOAD" "1" "Apr 19, 2017" "1.22.0-DEV" "nghttp2"
+.TH "H2LOAD" "1" "Apr 24, 2017" "1.22.0" "nghttp2"
 .SH NAME
 h2load \- HTTP/2 benchmarking tool
 .

doc/nghttp.1

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-.TH "NGHTTP" "1" "Apr 19, 2017" "1.22.0-DEV" "nghttp2"
+.TH "NGHTTP" "1" "Apr 24, 2017" "1.22.0" "nghttp2"
 .SH NAME
 nghttp \- HTTP/2 client
 .

doc/nghttpd.1

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-.TH "NGHTTPD" "1" "Apr 19, 2017" "1.22.0-DEV" "nghttp2"
+.TH "NGHTTPD" "1" "Apr 24, 2017" "1.22.0" "nghttp2"
 .SH NAME
 nghttpd \- HTTP/2 server
 .

doc/nghttpx.1

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-.TH "NGHTTPX" "1" "Apr 19, 2017" "1.22.0-DEV" "nghttp2"
+.TH "NGHTTPX" "1" "Apr 24, 2017" "1.22.0" "nghttp2"
 .SH NAME
 nghttpx \- HTTP/2 proxy
 .
@@ -1505,7 +1505,9 @@ Set mruby script file
 .INDENT 0.0
 .TP
 .B \-\-conf=<PATH>
-Load configuration from <PATH>.
+Load  configuration  from   <PATH>.   Please  note  that
+nghttpx always  tries to read the  default configuration
+file if \fI\%\-\-conf\fP is not given.
 .sp
 Default: \fB/etc/nghttpx/nghttpx.conf\fP
 .UNINDENT

doc/nghttpx.1.rst

@@ -1377,7 +1377,9 @@ Misc
 
 .. option:: --conf=<PATH>
 
-    Load configuration from <PATH>.
+    Load  configuration  from   <PATH>.   Please  note  that
+    nghttpx always  tries to read the  default configuration
+    file if :option:`--conf` is not given.
 
     Default: ``/etc/nghttpx/nghttpx.conf``