Initialize num and exposureAdjustment values to 0

[linuxkidd]

During compile a warning is issued for a possibly uninitialized variable. This is due to the declaration of these variables having no value, and no default 'else' is present to set them should none of the conditional tests match.

Added 0 and 0.0 values to the declaration of these variables to remove the compile warning.

capture.cpp: In function ‘int main(int, char**)’:
capture.cpp:2187:33: warning: ‘num’ may be used uninitialized in this function [-Wmaybe-uninitialized]
                          sprintf(textBuffer, "  > !!! Retrying @ %'ld us because '%s (%d)'\n", currentExposure, why.c_str(), num);
                          ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
capture.cpp:2094:48: warning: ‘exposureAdjustment’ may be used uninitialized in this function [-Wmaybe-uninitialized]
                         maxAcceptableHistogram *= exposureAdjustment;
                         ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~