installhtml: set default podpath to './lib'

Previously (as reported nine years ago by Nick Clark in what is now
#11859), the default setting for
'podpath' was '.'.  This meant that, unless you explicitly set a
colon-delimited list of directories as the value for 'podpath', all
files containing POD under '.' were HTML-ified and installed.  The only
directories that always should have HTML-ized POD installed are 'lib'
and 'pod' itself.

Invoking 'installhtml' like the following should now DTRT:

        export HTMLDIR=$HOMEDIR/tmp/installhtml && \
        ./perl -Ilib ./installhtml    \
            --htmldir=$HTMLDIR     \
            --htmlroot=$HTMLDIR    \
            --splithead=pod/perlipc     \
            --recurse \
            --verbose 2>&1 | tee installhtml.log

installhtml

@@ -46,7 +46,7 @@ Default is current directory.
 =item B<--podpath> POD search path
 
 The list of directories to search for .pod and .pm files to be converted.
-Default is 'podroot/.'.
+Default is 'podroot/lib'.
 
 =item B<--recurse> recurse on subdirectories
 
@@ -122,7 +122,7 @@ Usage: $0 --help --podpath=<name>:...:<name> --podroot=<name>
 
     --help      - this message
     --podpath   - colon-separated list of directories containing .pod and
-                  .pm files to be converted (. by default).
+                  .pm files to be converted ('lib/' by default).
     --podroot   - filesystem base directory from which all relative paths in
                   podpath stem (default is .).
     --htmldir   - directory to store resulting html files in relative
@@ -147,7 +147,7 @@ END_OF_USAGE
 my (@podpath, $podroot, $htmldir, $htmlroot, $recurse, @splithead,
     @splititem, $splitpod, $verbose, $pod2html, @ignore);
 
-@podpath = ( "." );	# colon-separated list of directories containing .pod
+@podpath = ( "lib" );	# colon-separated list of directories containing .pod
 			# and .pm files to be converted.
 $podroot = ".";		# assume the pods we want are here
 $htmldir = "";		# nothing for now...