sensors-detect: Fix use of uninitialized value 'vendor_id' on ppc64

Based on a report and an original patch from Jaromir Capik:

There's no vendor_id entry in the /proc/cpuinfo file in case of PPC64
systems and consequently the script returns 3 screens full of the
following errors:

Use of uninitialized value in string eq at /usr/sbin/sensors-detect
line 6444
Use of uninitialized value in string eq at /usr/sbin/sensors-detect
line 6459
Use of uninitialized value in string eq at /usr/sbin/sensors-detect
line 6473

CHANGES

@@ -14,6 +14,7 @@ SVN HEAD
                   Introduce automatic mode (--auto)
                   Detect incorrect non-interactive runs
                   Rework option handling
+                  Fix use of uninitialized value 'vendor_id' on ppc64
 
 3.3.4 (2013-05-27)
   sensors.conf.5: Mention "sensors -u" to get the raw feature names

prog/detect/sensors-detect

@@ -2694,7 +2694,10 @@ sub initialize_cpu_list
 	while (<INPUTFILE>) {
 		if (m/^processor\s*:\s*(\d+)/) {
 			push @cpu, $entry if scalar keys(%{$entry}); # Previous entry
-			$entry = { nr => $1 }; # New entry
+			$entry = { # New entry
+				nr => $1,
+				vendor_id => "undefined",
+			};
 			next;
 		}
 		if (m/^(vendor_id|cpu family|model|model name|stepping|cpuid level)\s*:\s*(.+)$/) {