Manpage generation tweaks

- depend on gnc-vcs-info.h file directly instead of the gnc-vcs-info target
  The latter won't cause gnucash to update the manpage in case gnc-vcs-info.h changes,
  the former does.
- use GNC_VCS_REV as version instead of the static VERSION parameter

doc/CMakeLists.txt

@@ -55,10 +55,9 @@ file(COPY ${CMAKE_CURRENT_BINARY_DIR}/tip_of_the_day.list
   DESTINATION ${DATADIR_BUILD}/gnucash)
 
 add_custom_command(OUTPUT gnucash.1
-  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/gnucash.1.in gnc-vcs-info
+  DEPENDS ${CMAKE_CURRENT_SOURCE_DIR}/gnucash.1.in ${VCS_INFO_FILE}
   COMMAND ${CMAKE_COMMAND} -D SRC=${CMAKE_CURRENT_SOURCE_DIR}/gnucash.1.in
                            -D DST=gnucash.1
-                           -D VERSION=${VERSION}
                            -D VCS_INFO_FILE=${VCS_INFO_FILE}
                            -D DATADIR_BUILD=${DATADIR_BUILD}
                            -D SRC_DIR=${CMAKE_SOURCE_DIR}

doc/gnucash.1.in

@@ -2,7 +2,7 @@
 .\" Process this file with
 .\" groff -man -Tascii foo.1
 .\"
-.TH GNUCASH 1 "@GNC_VCS_REV_DATE@" "Version @VERSION@" "GnuCash Manual Pages"
+.TH GNUCASH 1 "@GNC_VCS_REV_DATE@" "Version @GNC_VCS_REV@" "GnuCash Manual Pages"
 .SH NAME
 gnucash \- personal finance manager
 .SH SYNOPSIS