Install bitcoin-wallet manpage.

This change marks the already-existing bitcoin-wallet.1 manpage file for
installation together with the others.  Previously, only bitcoind.1,
bitcoin-cli.1, bitcoin-tx.1 and bitcoin-qt.1 would be installed.

Author: domob1812

doc/man/Makefile.am

@@ -15,3 +15,9 @@ endif
 if BUILD_BITCOIN_TX
   dist_man1_MANS+=bitcoin-tx.1
 endif
+
+if ENABLE_WALLET
+if BUILD_BITCOIN_WALLET
+  dist_man1_MANS+=bitcoin-wallet.1
+endif
+endif