[Rd] axTicks on a reverse ylog plot (PR#7973)

[mwtoews@sfu.ca]

There is still issues with the reversed y-log scale plot:

# Test case A: works as expected
plot(10:100,log="y",ylim=c(100,11))
grid()
par("yaxp")

# Test case B: grid does not have horizontal lines; par("yaxp") is  
different
plot(1:100,log="y",ylim=c(100,10))
grid()
par("yaxp")

In the second test case, axTicks for the horizontal lines (in grid())  
returns numeric(0) for spacing ... how do the tick marks get drawn in  
the first place??
-mt

--please do not edit the information below--

Version:
platform = powerpc-apple-darwin8.1.0
arch = powerpc
os = darwin8.1.0
system = powerpc, darwin8.1.0
status = Patched
major = 2
minor = 1.1
year = 2005
month = 06
day = 26
language = R

Locale:
en_CA.UTF-8/en_CA.UTF-8/en_CA.UTF-8/C/en_CA.UTF-8/en_CA.UTF-8

Search Path:
.GlobalEnv, package:methods, package:stats, package:graphics,  
package:grDevices, package:utils, package:datasets, Autoloads,  
package:base